diff --git a/spec/core_functions/math/abs.hrx b/spec/core_functions/math/abs.hrx
index cc9e2f868..faaf3ec47 100644
--- a/spec/core_functions/math/abs.hrx
+++ b/spec/core_functions/math/abs.hrx
@@ -1,5 +1,12 @@
+<===> options.yml
+---
+:ignore_for:
+- libsass
+
+<===>
+================================================================================
 <===> zero/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(0)}
 
 <===> zero/output.css
@@ -10,7 +17,7 @@ a {
 <===>
 ================================================================================
 <===> positive/integer/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(1)}
 
 <===> positive/integer/output.css
@@ -21,7 +28,7 @@ a {
 <===>
 ================================================================================
 <===> positive/decimal/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(5.6)}
 
 <===> positive/decimal/output.css
@@ -32,7 +39,7 @@ a {
 <===>
 ================================================================================
 <===> negative/integer/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(-17)}
 
 <===> negative/integer/output.css
@@ -43,7 +50,7 @@ a {
 <===>
 ================================================================================
 <===> negative/decimal/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(-123.456)}
 
 <===> negative/decimal/output.css
@@ -58,7 +65,7 @@ a {
   - sass/libsass#2887
 
 <===> preserves_units/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(-7px / 4em) * 1em}
 
 <===> preserves_units/output.css
@@ -82,9 +89,8 @@ More info and automated migrator: https://sass-lang.com/d/slash-div
 <===>
 ================================================================================
 <===> named/input.scss
-@use "sass:math" as math;
-$number: -3;
-a {b: math.abs($number)}
+@use "sass:math";
+a { b: math.abs($number: 3)}
 
 <===> named/output.css
 a {
@@ -94,7 +100,7 @@ a {
 <===>
 ================================================================================
 <===> error/type/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(c)}
 
 <===> error/type/error
@@ -116,7 +122,7 @@ Error: argument `$number` of `math.abs($number)` must be a number
 <===>
 ================================================================================
 <===> error/too_few_args/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs()}
 
 <===> error/too_few_args/error
@@ -141,7 +147,7 @@ Error: Function abs is missing argument $number.
 <===>
 ================================================================================
 <===> error/too_many_args/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: math.abs(1, 2)}
 
 <===> error/too_many_args/error
diff --git a/spec/core_functions/math/pow/arguments.hrx b/spec/core_functions/math/pow/arguments.hrx
index b8efdfccd..39e542f50 100644
--- a/spec/core_functions/math/pow/arguments.hrx
+++ b/spec/core_functions/math/pow/arguments.hrx
@@ -42,7 +42,7 @@ Error: $exponent: "0" is not a number.
 a {b: math.pow(1px, 0)}
 
 <===> error/base_has_units/error
-Error: Expected 1px to have no units.
+Error: $base: Expected 1px to have no units.
   ,
 2 | a {b: math.pow(1px, 0)}
   |       ^^^^^^^^^^^^^^^^
@@ -56,7 +56,7 @@ Error: Expected 1px to have no units.
 a {b: math.pow(0, 1px)}
 
 <===> error/exponent_has_units/error
-Error: Expected 1px to have no units.
+Error: $exponent: Expected 1px to have no units.
   ,
 2 | a {b: math.pow(0, 1px)}
   |       ^^^^^^^^^^^^^^^^
diff --git a/spec/core_functions/math/round.hrx b/spec/core_functions/math/round.hrx
index 157eca826..e448d16d1 100644
--- a/spec/core_functions/math/round.hrx
+++ b/spec/core_functions/math/round.hrx
@@ -1,3 +1,10 @@
+<===> options.yml
+---
+:ignore_for:
+- libsass
+
+<===>
+================================================================================
 <===> integer/input.scss
 @use "sass:math";
 a {b: math.round(1)}
diff --git a/spec/core_functions/math/sqrt.hrx b/spec/core_functions/math/sqrt.hrx
index 9b635cd54..f6574c62c 100644
--- a/spec/core_functions/math/sqrt.hrx
+++ b/spec/core_functions/math/sqrt.hrx
@@ -112,7 +112,7 @@ Error: $number: "0" is not a number.
 a {b: math.sqrt(1px)}
 
 <===> error/units/error
-Error: Expected 1px to have no units.
+Error: $number: Expected 1px to have no units.
   ,
 2 | a {b: math.sqrt(1px)}
   |       ^^^^^^^^^^^^^^
diff --git a/spec/values/calculation/abs.hrx b/spec/values/calculation/abs.hrx
index b18e503e4..363cf5ab4 100644
--- a/spec/values/calculation/abs.hrx
+++ b/spec/values/calculation/abs.hrx
@@ -25,40 +25,117 @@ a {
 <===>
 ================================================================================
 <===> positive/decimal/input.scss
-a {b: abs(5.6)}
+a {b: abs(-5.6px)}
 
 <===> positive/decimal/output.css
 a {
-  b: 5.6;
+  b: 5.6px;
 }
 
 <===>
 ================================================================================
-<===> negative/integer/input.scss
-a {b: abs(-17)}
+<===> operation/integer/input.scss
+a {b: abs(17 * 5%)}
 
-<===> negative/integer/output.css
+<===> operation/integer/output.css
 a {
-  b: 17;
+  b: 85%;
 }
 
+<===> operation/integer/warning
+DEPRECATION WARNING: Passing percentage units to the global abs() function is deprecated.
+In the future, this will emit a CSS abs() function to be resolved by the browser.
+
+To preserve current behavior:
+math.abs(85%)
+To emit a CSS abs() now:
+abs(#{85%})
+More info: https://sass-lang.com/documentation/values/calculations#abs
+  ,
+1 | a {b: abs(17 * 5%)}
+  | ^^^^^^^^^^^^^^^^^^^
+  '
+    input.scss 1:1  root stylesheet
+
 <===>
 ================================================================================
-<===> negative/decimal/input.scss
-a {b: abs(-123.456)}
+<===> operation/variable/input.scss
+a {
+  --test: 5;
+  b: abs(1px + 2px - var(--test))
+}
 
-<===> negative/decimal/output.css
+<===> operation/variable/output.css
 a {
-  b: 123.456;
+  --test: 5;
+  b: abs(3px - var(--test));
 }
 
 <===>
 ================================================================================
-<===> named/input.scss
-$number: -3;
-a {b: abs($number)}
+<===> operation/incompatible_units/input.scss
+a {b: abs(17px * 5%)}
+
+<===> operation/incompatible_units/error
+Error: 85px*% isn't a valid CSS value.
+  ,
+1 | a {b: abs(17px * 5%)}
+  |       ^^^^^^^^^^^^^^
+  '
+  input.scss 1:7  root stylesheet
 
-<===> named/output.css
+<===>
+================================================================================
+<===> preserved/operation/incompatible_units/input.scss
+a {b: abs(17px + 5%)}
+
+<===> preserved/operation/incompatible_units/output.css
+a {
+  b: abs(17px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: abs(var(--test))
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: abs(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unknown_variable/input.scss
+a {b: abs(test)}
+
+<===> preserved/unknown_variable/output.css
+a {
+  b: abs(test);
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: abs(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: abs(test);
+}
+
+<===>
+================================================================================
+<===> named_argument/input.scss
+a {b: abs($number: -3)}
+
+<===> named_argument/output.css
 a {
   b: 3;
 }
@@ -70,7 +147,7 @@ a {b: abs(-7px / 4em) * 1em}
 
 <===> preserves_units/output.css
 a {
-  b: 1.75em;
+  b: 1.75px;
 }
 
 <===>
@@ -79,26 +156,33 @@ a {
 a {b: abs()}
 
 <===> error/too_few_args/error
-Error: Expected number, variable, function, or calculation.
-  ,
+Error: Missing argument $number.
+  ,--> input.scss
 1 | a {b: abs()}
-  |           ^
+  |       ^^^^^ invocation
+  '
+  ,--> sass:math
+1 | @function abs($number) {
+  |           ============ declaration
   '
-  input.scss 1:11  root stylesheet
+  input.scss 1:7  root stylesheet
 
 <===>
 ================================================================================
 <===> error/too_many_args/input.scss
 a {b: abs(1, 2)}
 
-
 <===> error/too_many_args/error
-Error: expected "+", "-", "*", "/", or ")".
-  ,
+Error: Only 1 argument allowed, but 2 were passed.
+  ,--> input.scss
 1 | a {b: abs(1, 2)}
-  |            ^
+  |       ^^^^^^^^^ invocation
+  '
+  ,--> sass:math
+1 | @function abs($number) {
+  |           ============ declaration
   '
-  input.scss 1:12  root stylesheet
+  input.scss 1:7  root stylesheet
 
 <===>
 ================================================================================
@@ -107,16 +191,18 @@ a {b: abs(-7.5%)}
 
 <===> abs_percentage_warning/output.css
 a {
-  b: 7.5;
+  b: 7.5%;
 }
 
 <===> abs_percentage_warning/warning
-DEPRECATION WARNING: Passing percentage units to the global abs() function is deprecated In the future, this will emit a CSS abs() function to be resolved by the browser.
+DEPRECATION WARNING: Passing percentage units to the global abs() function is deprecated.
+In the future, this will emit a CSS abs() function to be resolved by the browser.
+
 To preserve current behavior:
 math.abs(-7.5%)
 To emit a CSS abs() now:
 abs(#{-7.5%})
-More info: https://sass-lang.com/d/abs-percent
+More info: https://sass-lang.com/documentation/values/calculations#abs
   ,
 1 | a {b: abs(-7.5%)}
   | ^^^^^^^^^^^^^^^^^
diff --git a/spec/values/calculation/acos.hrx b/spec/values/calculation/acos.hrx
index a9c52d66a..f5aaf25a7 100644
--- a/spec/values/calculation/acos.hrx
+++ b/spec/values/calculation/acos.hrx
@@ -74,14 +74,67 @@ a {
 
 <===>
 ================================================================================
-<===> units/input.scss
-a {b: acos(1px)}
+<===> preserved/percent/input.scss
+a {b: acos(3px - 1.5px + 5%)}
 
-<===> units/output.css
+<===> preserved/percent/output.css
 a {
-  b: 0deg;
+  b: acos(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: acos(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: acos(2px + var(--test));
 }
 
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: acos(var(--test));
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: acos(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: acos(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: acos(test);
+}
+
+<===>
+================================================================================
+<===> units/input.scss
+a {b: acos(1px)}
+
+<===> units/error
+Error: $number: Expected 1px to have no units.
+  ,
+1 | a {b: acos(1px)}
+  |       ^^^^^^^^^
+  '
+  input.scss 1:7  root stylesheet
+
 <===>
 ================================================================================
 <===> error/type/input.scss
diff --git a/spec/values/calculation/asin.hrx b/spec/values/calculation/asin.hrx
index 86bedf489..ad3321fa3 100644
--- a/spec/values/calculation/asin.hrx
+++ b/spec/values/calculation/asin.hrx
@@ -107,10 +107,13 @@ a {
 <===> units/input.scss
 a {b: asin(1px)}
 
-<===> units/output.css
-a {
-  b: 90deg;
-}
+<===> units/error
+Error: $number: Expected 1px to have no units.
+  ,
+1 | a {b: asin(1px)}
+  |       ^^^^^^^^^
+  '
+  input.scss 1:7  root stylesheet
 
 <===>
 ================================================================================
@@ -122,6 +125,56 @@ a {
   b: asin(1%);
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: asin(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: asin(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: asin(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: asin(2px + var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: asin(var(--test));
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: asin(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: asin(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: asin(test);
+}
+
 <===>
 ================================================================================
 <===> error/type/input.scss
diff --git a/spec/values/calculation/atan.hrx b/spec/values/calculation/atan.hrx
index b06b95cc9..5def26f8b 100644
--- a/spec/values/calculation/atan.hrx
+++ b/spec/values/calculation/atan.hrx
@@ -5,7 +5,7 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> negative_infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: atan(math.div(-1, 0))}
 
 <===> negative_infinity/output.css
@@ -76,7 +76,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: atan(math.div(1, 0))}
 
 <===> infinity/output.css
@@ -89,9 +89,62 @@ a {
 <===> units/input.scss
 a {b: atan(1px)}
 
-<===> units/output.css
+<===> units/error
+Error: $number: Expected 1px to have no units.
+  ,
+1 | a {b: atan(1px)}
+  |       ^^^^^^^^^
+  '
+  input.scss 1:7  root stylesheet
+
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: atan(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
 a {
-  b: 45deg;
+  b: atan(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: atan(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: atan(2px + var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: atan(var(--test));
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: atan(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: atan(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: atan(test);
 }
 
 <===>
diff --git a/spec/values/calculation/atan2.hrx b/spec/values/calculation/atan2.hrx
index f7323ffb0..d12cb6b31 100644
--- a/spec/values/calculation/atan2.hrx
+++ b/spec/values/calculation/atan2.hrx
@@ -34,20 +34,55 @@ a {
   b: atan2(1%, 1cm);
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: atan2(4px, 3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: atan2(4px, 1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: atan2(3px - 1px + var(--test), 4px);
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: atan2(2px + var(--test), 4px);
+}
+
 <===>
 ================================================================================
 <===> preserved/variable/input.scss
 a {
-  --two-args: 2, 3;
-  b: atan2(var(--two-args));
+  --test: 5;
+  b: atan2(var(--test));
 }
 
 <===> preserved/variable/output.css
 a {
-  --two-args: 2, 3;
-  b: atan2(var(--two-args));
+  --test: 5;
+  b: atan2(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: atan2(test);
 }
 
+<===> preserved/unquoted_string/output.css
+a {
+  b: atan2(test);
+}
 
 <===>
 ================================================================================
@@ -168,3 +203,16 @@ Error: expected "+", "-", "*", "/", or ")".
   |                 ^
   '
   input.scss 1:17  root stylesheet
+
+<===>
+================================================================================
+<===> error/syntax/quoted_string/input.scss
+a {b: atan2("test")}
+
+<===> error/syntax/quoted_string/error
+Error: Expected number, variable, function, or calculation.
+  ,
+1 | a {b: atan2("test")}
+  |             ^
+  '
+  input.scss 1:13  root stylesheet
diff --git a/spec/values/calculation/cos.hrx b/spec/values/calculation/cos.hrx
index 1aa98ad9b..79219392f 100644
--- a/spec/values/calculation/cos.hrx
+++ b/spec/values/calculation/cos.hrx
@@ -5,7 +5,7 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> negative_infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: cos(math.div(-1, 0))}
 
 <===> negative_infinity/output.css
@@ -16,7 +16,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: cos(math.div(1, 0))}
 
 <===> infinity/output.css
@@ -95,6 +95,56 @@ a {
   b: 0.5403023059;
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: cos(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: cos(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: cos(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: cos(2px + var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: cos(var(--test));
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: cos(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: cos(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: cos(test);
+}
+
 <===>
 ================================================================================
 <===> error/type/input.scss
diff --git a/spec/values/calculation/exp.hrx b/spec/values/calculation/exp.hrx
index 80e987578..5633606ec 100644
--- a/spec/values/calculation/exp.hrx
+++ b/spec/values/calculation/exp.hrx
@@ -79,44 +79,80 @@ a {
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/result_is_integer/input.scss
+<===> operation/unitless/result_is_integer/input.scss
 a {b: exp(5)}
 
-<===> preserved/operation/unitless/result_is_integer/output.css
+<===> operation/unitless/result_is_integer/output.css
 a {
   b: 148.4131591026;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/result_is_long/input.scss
+<===> operation/unitless/result_is_long/input.scss
 a {b: exp(1000.65)}
 
-<===> preserved/operation/unitless/result_is_long/output.css
+<===> operation/unitless/result_is_long/output.css
 a {
   b: calc(infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math_nested/negative/input.scss
+<===> operation/math_nested/negative/input.scss
 a {b: calc(exp(5 * 8 - 100))}
 
-<===> preserved/operation/math_nested/negative/output.css
+<===> operation/math_nested/negative/output.css
 a {
   b: 0;
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: exp(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: exp(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: exp(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: exp(2px + var(--test));
+}
+
 <===>
 ================================================================================
 <===> preserved/variable/input.scss
 a {
-  --one-arg: 2;
-  b: exp(var(--one-arg));
+  --test: 5;
+  b: exp(var(--test));
 }
 
 <===> preserved/variable/output.css
 a {
-  --one-arg: 2;
-  b: exp(var(--one-arg));
+  --test: 5;
+  b: exp(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: exp(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: exp(test);
 }
diff --git a/spec/values/calculation/hypot.hrx b/spec/values/calculation/hypot.hrx
index 605837070..74465f8fb 100644
--- a/spec/values/calculation/hypot.hrx
+++ b/spec/values/calculation/hypot.hrx
@@ -15,7 +15,7 @@ a {
 <===>
 ================================================================================
 <===> compatible_units/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: hypot(3cm, 4mm * 10, 5q * 40, math.div(6in, 2.54), 7px * math.div(96, 2.54))}
 
 <===> compatible_units/output.css
@@ -26,7 +26,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/first/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: hypot(math.div(1, 0), 1, 1)}
 
 <===> infinity/first/output.css
@@ -37,7 +37,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/second/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: hypot(1, math.div(1, 0), 1)}
 
 <===> infinity/second/output.css
@@ -48,7 +48,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/third/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: hypot(1, 1, math.div(1, 0))}
 
 <===> infinity/third/output.css
@@ -59,7 +59,7 @@ a {
 <===>
 ================================================================================
 <===> math/plus/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: hypot(10*3, 15, 70/2)}
 
 <===> math/plus/output.css
@@ -70,7 +70,7 @@ a {
 <===>
 ================================================================================
 <===> percentage/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: hypot(10%, 5%)}
 
 <===> percentage/output.css
@@ -108,6 +108,42 @@ b {
   a: hypot(var(--example));
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: hypot(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: hypot(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: hypot(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: hypot(2px + var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: hypot(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: hypot(test);
+}
+
 <===>
 ================================================================================
 <===> error/type/first/input.scss
diff --git a/spec/values/calculation/log.hrx b/spec/values/calculation/log.hrx
index bfb0251a8..d4be41555 100644
--- a/spec/values/calculation/log.hrx
+++ b/spec/values/calculation/log.hrx
@@ -45,7 +45,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: log(math.div(1, 0))}
 
 <===> infinity/output.css
@@ -180,6 +180,29 @@ a {
   b: log(var(--two-args));
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: log(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: log(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: log(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: log(2px + var(--test));
+}
 
 <===>
 ================================================================================
@@ -243,3 +266,16 @@ Error: expected "+", "-", "*", "/", or ")".
   |               ^
   '
   input.scss 1:15  root stylesheet
+
+<===>
+================================================================================
+<===> error/syntax/quoted_string/input.scss
+a {b: log("test")}
+
+<===> error/syntax/quoted_string/error
+Error: Expected number, variable, function, or calculation.
+  ,
+1 | a {b: log("test")}
+  |           ^
+  '
+  input.scss 1:11  root stylesheet
diff --git a/spec/values/calculation/min.hrx b/spec/values/calculation/min.hrx
index c453129d7..acc4bc4ec 100644
--- a/spec/values/calculation/min.hrx
+++ b/spec/values/calculation/min.hrx
@@ -213,60 +213,60 @@ a {
 
 <===>
 ================================================================================
-<===> perserved/math/first/input.scss
+<===> preserved/math/first/input.scss
 a {b: min(1% + 1px, 2px)}
 
-<===> perserved/math/first/output.css
+<===> preserved/math/first/output.css
 a {
   b: min(1% + 1px, 2px);
 }
 
 <===>
 ================================================================================
-<===> perserved/math/second/input.scss
+<===> preserved/math/second/input.scss
 a {b: min(1px, 1% + 2px)}
 
-<===> perserved/math/second/output.css
+<===> preserved/math/second/output.css
 a {
   b: min(1px, 1% + 2px);
 }
 
 <===>
 ================================================================================
-<===> perserved/math/third/input.scss
+<===> preserved/math/third/input.scss
 a {b: min(1px, 2px, 1% + 3px)}
 
-<===> perserved/math/third/output.css
+<===> preserved/math/third/output.css
 a {
   b: min(1px, 2px, 1% + 3px);
 }
 
 <===>
 ================================================================================
-<===> perserved/unit/first/input.scss
+<===> preserved/unit/first/input.scss
 a {b: min(1%, 2px)}
 
-<===> perserved/unit/first/output.css
+<===> preserved/unit/first/output.css
 a {
   b: min(1%, 2px);
 }
 
 <===>
 ================================================================================
-<===> perserved/unit/second/input.scss
+<===> preserved/unit/second/input.scss
 a {b: min(1px, 2%)}
 
-<===> perserved/unit/second/output.css
+<===> preserved/unit/second/output.css
 a {
   b: min(1px, 2%);
 }
 
 <===>
 ================================================================================
-<===> perserved/unit/third/input.scss
+<===> preserved/unit/third/input.scss
 a {b: min(1px, 2px, 3%)}
 
-<===> perserved/unit/third/output.css
+<===> preserved/unit/third/output.css
 a {
   b: min(1px, 2px, 3%);
 }
diff --git a/spec/values/calculation/mod.hrx b/spec/values/calculation/mod.hrx
index 992486899..c0678fe9b 100644
--- a/spec/values/calculation/mod.hrx
+++ b/spec/values/calculation/mod.hrx
@@ -5,55 +5,55 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> error/syntax/no_arg/input.scss
-a {b: calc(mod())}
+a {b: mod()}
 
 <===> error/syntax/no_arg/error
 Error: Expected number, variable, function, or calculation.
   ,
-1 | a {b: calc(mod())}
-  |                ^
+1 | a {b: mod()}
+  |           ^
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/missing_arg/input.scss
-a {b: calc(mod(3))}
+a {b: mod(3)}
 
 <===> error/syntax/missing_arg/error
 Error: 2 arguments required, but only 1 was passed.
   ,
-1 | a {b: calc(mod(3))}
-  |            ^^^^^^
+1 | a {b: mod(3)}
+  |       ^^^^^^
   '
-  input.scss 1:12  root stylesheet
+  input.scss 1:7  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/many_args/input.scss
-a {b: calc(mod(3, 2, 1))}
+a {b: mod(3, 2, 1)}
 
 <===> error/syntax/many_args/error
 Error: expected "+", "-", "*", "/", or ")".
   ,
-1 | a {b: calc(mod(3, 2, 1))}
-  |                    ^
+1 | a {b: mod(3, 2, 1)}
+  |               ^
   '
-  input.scss 1:20  root stylesheet
+  input.scss 1:15  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/incompatible/input.scss
-a {b: calc(mod(16px, 5))}
+a {b: mod(16px, 5)}
 
 <===> error/syntax/incompatible/error
 Error: 16px and 5 are incompatible.
   ,
-1 | a {b: calc(mod(16px, 5))}
-  |                ^^^^ 16px
-  |                      = 5
+1 | a {b: mod(16px, 5)}
+  |           ^^^^ 16px
+  |                 = 5
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
@@ -71,29 +71,42 @@ Error: 1 and 16px are incompatible.
 <===>
 ================================================================================
 <===> error/syntax/min_incompatible/input.scss
-a {b: calc(mod(min(16, 9px), 6))}
+a {b: mod(min(16, 9px), 6)}
 
 <===> error/syntax/min_incompatible/error
 Error: 9px and 6 are incompatible.
   ,
-1 | a {b: calc(mod(min(16, 9px), 6))}
-  |                ^^^^^^^^^^^^ 9px
-  |                              = 6
+1 | a {b: mod(min(16, 9px), 6)}
+  |           ^^^^^^^^^^^^ 9px
+  |                         = 6
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/invalid_arg/input.scss
-a {b: calc(mod($))}
+a {b: mod($)}
 
 <===> error/syntax/invalid_arg/error
 Error: Expected identifier.
   ,
-1 | a {b: calc(mod($))}
-  |                 ^
+1 | a {b: mod($)}
+  |            ^
+  '
+  input.scss 1:12  root stylesheet
+
+<===>
+================================================================================
+<===> error/syntax/quoted_string/input.scss
+a {b: mod("test")}
+
+<===> error/syntax/quoted_string/error
+Error: Expected number, variable, function, or calculation.
+  ,
+1 | a {b: mod("test")}
+  |           ^
   '
-  input.scss 1:17  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
@@ -111,112 +124,112 @@ Error: Number 1px*px isn't compatible with CSS calculations.
 <===>
 ================================================================================
 <===> error/unit/input.scss
-a {b: calc(mod(5%, 3%))}
+a {b: mod(5%, 3%)}
 
 <===> error/unit/output.css
 a {
-  b: mod(5%, 3%);
+  b: 2%;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/positive_args/input.scss
+<===> operation/unitless/positive_args/input.scss
 a {b: mod(7, 3)}
 
-<===> preserved/operation/unitless/positive_args/output.css
+<===> operation/unitless/positive_args/output.css
 a {
   b: 1;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/y_negative/input.scss
+<===> operation/unitless/y_negative/input.scss
 a {b: mod(7, -3)}
 
-<===> preserved/operation/unitless/y_negative/output.css
+<===> operation/unitless/y_negative/output.css
 a {
   b: -2;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/x_negative/input.scss
+<===> operation/unitless/x_negative/input.scss
 a {b: mod(-7, 3)}
 
-<===> preserved/operation/unitless/x_negative/output.css
+<===> operation/unitless/x_negative/output.css
 a {
   b: 2;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/negative_args/input.scss
+<===> operation/unitless/negative_args/input.scss
 a {b: mod(-7, -3)}
 
-<===> preserved/operation/unitless/negative_args/output.css
+<===> operation/unitless/negative_args/output.css
 a {
   b: -1;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/y_zero/plus/input.scss
+<===> operation/y_zero/plus/input.scss
 a {b: mod(6, 0)}
 
-<===> preserved/operation/y_zero/plus/output.css
+<===> operation/y_zero/plus/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/x_zero/plus/input.scss
+<===> operation/x_zero/plus/input.scss
 a {b: mod(0, 6)}
 
-<===> preserved/operation/x_zero/plus/output.css
+<===> operation/x_zero/plus/output.css
 a {
   b: 0;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/zeros/plus/input.scss
+<===> operation/zeros/plus/input.scss
 a {b: mod(0, 0)}
 
-<===> preserved/operation/zeros/plus/output.css
+<===> operation/zeros/plus/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/y_infinity/plus/input.scss
-@use "sass:math" as math;
+<===> operation/y_infinity/plus/input.scss
+@use "sass:math";
 a {b: mod(math.div(1, 0), 10)}
 
-<===> preserved/operation/y_infinity/plus/output.css
+<===> operation/y_infinity/plus/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/x_infinity/plus/input.scss
-@use "sass:math" as math;
+<===> operation/x_infinity/plus/input.scss
+@use "sass:math";
 a {b: mod(10, math.div(1, 0))}
 
-<===> preserved/operation/x_infinity/plus/output.css
+<===> operation/x_infinity/plus/output.css
 a {
   b: 10;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/x_infinity/negative/input.scss
-@use "sass:math" as math;
+<===> operation/x_infinity/negative/input.scss
+@use "sass:math";
 a {b: mod(10, -infinity)}
 
-<===> preserved/operation/x_infinity/negative/output.css
+<===> operation/x_infinity/negative/output.css
 a {
   b: calc(NaN);
 }
@@ -234,3 +247,27 @@ a {
   --two-args: 2, 3;
   b: mod(var(--two-args));
 }
+
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: mod(4px, 3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: mod(4px, 1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: mod(3px - 1px + var(--test), 4px);
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: mod(2px + var(--test), 4px);
+}
diff --git a/spec/values/calculation/pow.hrx b/spec/values/calculation/pow.hrx
index 54f97d884..9619b8f04 100644
--- a/spec/values/calculation/pow.hrx
+++ b/spec/values/calculation/pow.hrx
@@ -5,55 +5,68 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> error/syntax/no_arg/input.scss
-a {b: calc(pow())}
+a {b: pow()}
 
 <===> error/syntax/no_arg/error
 Error: Expected number, variable, function, or calculation.
   ,
-1 | a {b: calc(pow())}
-  |                ^
+1 | a {b: pow()}
+  |           ^
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/missing_arg/input.scss
-a {b: calc(pow(3))}
+a {b: pow(3)}
 
 <===> error/syntax/missing_arg/error
 Error: 2 arguments required, but only 1 was passed.
   ,
-1 | a {b: calc(pow(3))}
-  |            ^^^^^^
+1 | a {b: pow(3)}
+  |       ^^^^^^
   '
-  input.scss 1:12  root stylesheet
+  input.scss 1:7  root stylesheet
+
+<===>
+================================================================================
+<===> error/syntax/quoted_string/input.scss
+a {b: pow("test")}
+
+<===> error/syntax/quoted_string/error
+Error: Expected number, variable, function, or calculation.
+  ,
+1 | a {b: pow("test")}
+  |           ^
+  '
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/many_args/input.scss
-a {b: calc(pow(3, 2, 1))}
+a {b: pow(3, 2, 1)}
 
 <===> error/syntax/many_args/error
 Error: expected "+", "-", "*", "/", or ")".
   ,
-1 | a {b: calc(pow(3, 2, 1))}
-  |                    ^
+1 | a {b: pow(3, 2, 1)}
+  |               ^
   '
-  input.scss 1:20  root stylesheet
+  input.scss 1:15  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/incompatible/input.scss
-a {b: calc(pow(16px, 5))}
+a {b: pow(16px, 5)}
 
 <===> error/syntax/incompatible/error
 Error: 16px and 5 are incompatible.
   ,
-1 | a {b: calc(pow(16px, 5))}
-  |                ^^^^ 16px
-  |                      = 5
+1 | a {b: pow(16px, 5)}
+  |           ^^^^ 16px
+  |                 = 5
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
@@ -71,29 +84,29 @@ Error: 1 and 16px are incompatible.
 <===>
 ================================================================================
 <===> error/syntax/min_incompatible/input.scss
-a {b: calc(pow(min(16, 9px), 6))}
+a {b: pow(min(16, 9px), 6)}
 
 <===> error/syntax/min_incompatible/error
 Error: 9px and 6 are incompatible.
   ,
-1 | a {b: calc(pow(min(16, 9px), 6))}
-  |                ^^^^^^^^^^^^ 9px
-  |                              = 6
+1 | a {b: pow(min(16, 9px), 6)}
+  |           ^^^^^^^^^^^^ 9px
+  |                         = 6
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/invalid_arg/input.scss
-a {b: calc(pow($))}
+a {b: pow($)}
 
 <===> error/syntax/invalid_arg/error
 Error: Expected identifier.
   ,
-1 | a {b: calc(pow($))}
-  |                 ^
+1 | a {b: pow($)}
+  |            ^
   '
-  input.scss 1:17  root stylesheet
+  input.scss 1:12  root stylesheet
 
 <===>
 ================================================================================
@@ -111,7 +124,7 @@ Error: Number 1px*px isn't compatible with CSS calculations.
 <===>
 ================================================================================
 <===> error/unit/input.scss
-a {b: calc(pow(5%, 3%))}
+a {b: pow(5%, 3%)}
 
 <===> error/unit/output.css
 a {
@@ -120,60 +133,60 @@ a {
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/result_is_integer/input.scss
+<===> operation/unitless/result_is_integer/input.scss
 a {b: pow(2, 3)}
 
-<===> preserved/operation/unitless/result_is_integer/output.css
+<===> operation/unitless/result_is_integer/output.css
 a {
   b: 8;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/result_is_long/input.scss
+<===> operation/unitless/result_is_long/input.scss
 a {b: pow(10, 10)}
 
-<===> preserved/operation/unitless/result_is_long/output.css
+<===> operation/unitless/result_is_long/output.css
 a {
   b: 10000000000;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math_nested/minus/input.scss
-a {b: calc(pow(3 - 1, 2))}
+<===> operation/math_nested/minus/input.scss
+a {b: pow(3 - 1, 2)}
 
-<===> preserved/operation/math_nested/minus/output.css
+<===> operation/math_nested/minus/output.css
 a {
   b: 4;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math/plus/input.scss
+<===> operation/math/plus/input.scss
 a {b: pow(10 + 6, 0)}
 
-<===> preserved/operation/math/plus/output.css
+<===> operation/math/plus/output.css
 a {
   b: 1;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math/max/input.scss
+<===> operation/math/max/input.scss
 a {b: pow(max(2, 9), 2)}
 
-<===> preserved/operation/math/max/output.css
+<===> operation/math/max/output.css
 a {
   b: 81;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math/min/input.scss
+<===> operation/math/min/input.scss
 a {b: pow(min(2, 9), 5)}
 
-<===> preserved/operation/math/min/output.css
+<===> operation/math/min/output.css
 a {
   b: 32;
 }
@@ -191,3 +204,39 @@ a {
   --two-args: 2, 3;
   b: pow(var(--two-args));
 }
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: pow(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: pow(test);
+}
+
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: pow(4px, 3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: pow(4px, 1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: pow(3px - 1px + var(--test), 4px);
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: pow(2px + var(--test), 4px);
+}
diff --git a/spec/values/calculation/rem.hrx b/spec/values/calculation/rem.hrx
index 080f91b79..fa28599c2 100644
--- a/spec/values/calculation/rem.hrx
+++ b/spec/values/calculation/rem.hrx
@@ -5,55 +5,55 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> error/syntax/no_arg/input.scss
-a {b: calc(rem())}
+a {b: rem()}
 
 <===> error/syntax/no_arg/error
 Error: Expected number, variable, function, or calculation.
   ,
-1 | a {b: calc(rem())}
-  |                ^
+1 | a {b: rem()}
+  |           ^
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/missing_arg/input.scss
-a {b: calc(rem(3))}
+a {b: rem(3)}
 
 <===> error/syntax/missing_arg/error
 Error: 2 arguments required, but only 1 was passed.
   ,
-1 | a {b: calc(rem(3))}
-  |            ^^^^^^
+1 | a {b: rem(3)}
+  |       ^^^^^^
   '
-  input.scss 1:12  root stylesheet
+  input.scss 1:7  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/many_args/input.scss
-a {b: calc(rem(3, 2, 1))}
+a {b: rem(3, 2, 1)}
 
 <===> error/syntax/many_args/error
 Error: expected "+", "-", "*", "/", or ")".
   ,
-1 | a {b: calc(rem(3, 2, 1))}
-  |                    ^
+1 | a {b: rem(3, 2, 1)}
+  |               ^
   '
-  input.scss 1:20  root stylesheet
+  input.scss 1:15  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/incompatible/input.scss
-a {b: calc(rem(16px, 5))}
+a {b: rem(16px, 5)}
 
 <===> error/syntax/incompatible/error
 Error: 16px and 5 are incompatible.
   ,
-1 | a {b: calc(rem(16px, 5))}
-  |                ^^^^ 16px
-  |                      = 5
+1 | a {b: rem(16px, 5)}
+  |           ^^^^ 16px
+  |                 = 5
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
@@ -71,29 +71,42 @@ Error: 1 and 16px are incompatible.
 <===>
 ================================================================================
 <===> error/syntax/min_incompatible/input.scss
-a {b: calc(rem(min(16, 9px), 6))}
+a {b: rem(min(16, 9px), 6)}
 
 <===> error/syntax/min_incompatible/error
 Error: 9px and 6 are incompatible.
   ,
-1 | a {b: calc(rem(min(16, 9px), 6))}
-  |                ^^^^^^^^^^^^ 9px
-  |                              = 6
+1 | a {b: rem(min(16, 9px), 6)}
+  |           ^^^^^^^^^^^^ 9px
+  |                         = 6
   '
-  input.scss 1:16  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/invalid_arg/input.scss
-a {b: calc(rem($))}
+a {b: rem($)}
 
 <===> error/syntax/invalid_arg/error
 Error: Expected identifier.
   ,
-1 | a {b: calc(rem($))}
-  |                 ^
+1 | a {b: rem($)}
+  |            ^
+  '
+  input.scss 1:12  root stylesheet
+
+<===>
+================================================================================
+<===> error/syntax/quoted_string/input.scss
+a {b: rem("test")}
+
+<===> error/syntax/quoted_string/error
+Error: Expected number, variable, function, or calculation.
+  ,
+1 | a {b: rem("test")}
+  |           ^
   '
-  input.scss 1:17  root stylesheet
+  input.scss 1:11  root stylesheet
 
 <===>
 ================================================================================
@@ -110,123 +123,123 @@ Error: Number 1px*px isn't compatible with CSS calculations.
 
 <===>
 ================================================================================
-<===> error/unit/input.scss
-a {b: calc(rem(5%, 3%))}
+<===> percentage/unit/input.scss
+a {b: rem(5%, 3%)}
 
-<===> error/unit/output.css
+<===> percentage/unit/output.css
 a {
-  b: rem(5%, 3%);
+  b: 2%;
 }
 
 <===>
 ================================================================================
-<===> preserved/unitless/positive_args/input.scss
+<===> unitless/positive_args/input.scss
 a {b: rem(7, 3)}
 
-<===> preserved/unitless/positive_args/output.css
+<===> unitless/positive_args/output.css
 a {
   b: 1;
 }
 
 <===>
 ================================================================================
-<===> preserved/unitless/y_negative/input.scss
+<===> unitless/y_negative/input.scss
 a {b: rem(7, -3)}
 
-<===> preserved/unitless/y_negative/output.css
+<===> unitless/y_negative/output.css
 a {
   b: -9;
 }
 
 <===>
 ================================================================================
-<===> preserved/unitless/x_negative/input.scss
+<===> unitless/x_negative/input.scss
 a {b: rem(-7, 3)}
 
-<===> preserved/unitless/x_negative/output.css
+<===> unitless/x_negative/output.css
 a {
   b: 9;
 }
 
 <===>
 ================================================================================
-<===> preserved/unitless/negative_args/input.scss
+<===> unitless/negative_args/input.scss
 a {b: rem(-7, -3)}
 
-<===> preserved/unitless/negative_args/output.css
+<===> unitless/negative_args/output.css
 a {
   b: -1;
 }
 
 <===>
 ================================================================================
-<===> preserved/negative_zero/input.scss
-@use "sass:math" as math;
+<===> negative_zero/input.scss
+@use "sass:math";
 a {b: math.div(1, rem(-7, 7))}
 
-<===> preserved/negative_zero/output.css
+<===> negative_zero/output.css
 a {
   b: calc(-infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/positive_zero/input.scss
-@use "sass:math" as math;
+<===> positive_zero/input.scss
+@use "sass:math";
 a {b: math.div(1, rem(7, 7))}
 
-<===> preserved/positive_zero/output.css
+<===> positive_zero/output.css
 a {
   b: calc(infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/y_zero/plus/input.scss
+<===> y_zero/plus/input.scss
 a {b: rem(6, 0)}
 
-<===> preserved/y_zero/plus/output.css
+<===> y_zero/plus/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/x_zero/plus/input.scss
+<===> x_zero/plus/input.scss
 a {b: rem(0, 6)}
 
-<===> preserved/x_zero/plus/output.css
+<===> x_zero/plus/output.css
 a {
   b: 0;
 }
 
 <===>
 ================================================================================
-<===> preserved/zeros/plus/input.scss
+<===> zeros/plus/input.scss
 a {b: rem(0, 0)}
 
-<===> preserved/zeros/plus/output.css
+<===> zeros/plus/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/y_infinity/plus/input.scss
-@use "sass:math" as math;
+<===> y_infinity/plus/input.scss
+@use "sass:math";
 a {b: rem(math.div(1, 0), 10)}
 
-<===> preserved/y_infinity/plus/output.css
+<===> y_infinity/plus/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/x_infinity/plus/input.scss
+<===> x_infinity/plus/input.scss
 a {b: rem(10, infinity)}
 
-<===> preserved/x_infinity/plus/output.css
+<===> x_infinity/plus/output.css
 a {
   b: 10;
 }
@@ -244,3 +257,39 @@ a {
   --two-args: 2, 3;
   b: rem(var(--two-args));
 }
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: rem(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: rem(test);
+}
+
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: rem(4px, 3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: rem(4px, 1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: rem(3px - 1px + var(--test), 4px);
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: rem(2px + var(--test), 4px);
+}
diff --git a/spec/values/calculation/round.hrx b/spec/values/calculation/round.hrx
index 3aa38b324..cdbe303ec 100644
--- a/spec/values/calculation/round.hrx
+++ b/spec/values/calculation/round.hrx
@@ -59,16 +59,6 @@ Error: 3px must be either nearest, up, down or to-zero.
   '
   input.scss 1:7  root stylesheet
 
-<===>
-================================================================================
-<===> perserved/unknown_variable/number/input.scss
-a {b: round(test)}
-
-<===> perserved/unknown_variable/number/output.css
-a {
-  b: round(test);
-}
-
 <===>
 ================================================================================
 <===> error/variable/number_and_step/input.scss
@@ -84,256 +74,328 @@ Error: 4px must be either nearest, up, down or to-zero.
 
 <===>
 ================================================================================
-<===> perserved/unknown_variable/two_args/input.scss
+<===> preserved/unquoted_string/number/input.scss
+a {b: round(test)}
+
+<===> preserved/unquoted_string/number/output.css
+a {
+  b: round(test);
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/two_args/input.scss
 a {b: round(test, nearest)}
 
-<===> perserved/unknown_variable/two_args/output.css
+<===> preserved/unquoted_string/two_args/output.css
 a {
   b: round(test, nearest);
 }
 
 <===>
 ================================================================================
-<===> perserved/unknown_variable/one_arg/input.scss
+<===> preserved/unquoted_string/one_arg/input.scss
 a {b: round(test, 5)}
 
-<===> perserved/unknown_variable/one_arg/output.css
+<===> preserved/unquoted_string/one_arg/output.css
 a {
   b: round(test, 5);
 }
 
 <===>
 ================================================================================
-<===> perserved/unknown_variable/step/input.scss
+<===> preserved/unquoted_string/step/input.scss
 a {b: round(4px, nearest)}
 
-<===> perserved/unknown_variable/step/output.css
+<===> preserved/unquoted_string/step/output.css
 a {
   b: round(4px, nearest);
 }
 
 <===>
 ================================================================================
-<===> preserved/step/zero/input.scss
+<===> preserved/operation/two_args/math/input.scss
+a {b: round(3.4px + 10%, 1px + 4px)}
+
+<===> preserved/operation/two_args/math/output.css
+a {
+  b: round(3.4px + 10%, 5px);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/nearest/math/input.scss
+a {
+  --test: 3;
+  b: round(nearest, 3.8px - 1px + var(--test), 1.1px + 4px)}
+
+<===> preserved/operation/nearest/math/output.css
+a {
+  --test: 3;
+  b: round(nearest, 2.8px + var(--test), 5.1px);
+}
+
+<===>
+================================================================================
+<===> step/zero/input.scss
 a {b: round(5px, 0px)}
 
-<===> preserved/step/zero/output.css
+<===> step/zero/output.css
 a {
   b: calc(NaN * 1px);
 }
 
 <===>
 ================================================================================
-<===> preserved/step/infinity/input.scss
-@use "sass:math" as math;
+<===> step/infinity/input.scss
+@use "sass:math";
 a {b: round(-0, infinity)}
 
-<===> preserved/step/infinity/output.css
+<===> step/infinity/output.css
 a {
   b: 0;
 }
 
 <===>
 ================================================================================
-<===> preserved/step/number/input.scss
+<===> step/number/input.scss
 a {b: round(5px, 5px)}
 
-<===> preserved/step/number/output.css
+<===> step/number/output.css
 a {
   b: 5px;
 }
 
 <===>
 ================================================================================
-<===> preserved/number/infinity/input.scss
-@use "sass:math" as math;
+<===> step/unitless/input.scss
+a {b: round(5, 5)}
+
+<===> step/unitless/output.css
+a {
+  b: 5;
+}
+
+<===>
+================================================================================
+<===> step/compatible_units/input.scss
+a {b: round(100px, 2cm)}
+
+<===> step/compatible_units/output.css
+a {
+  b: 75.5905511811px;
+}
+
+<===>
+================================================================================
+<===> number/infinity/input.scss
+@use "sass:math";
 a {b: round(infinity, 5)}
 
-<===> preserved/number/infinity/output.css
+<===> number/infinity/output.css
 a {
   b: calc(infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/up/negative_zero/input.scss
-@use "sass:math" as math;
+<===> up/negative_zero/input.scss
+@use "sass:math";
 a {b: math.div(1, round(up, -10, infinity))}
 
-<===> preserved/up/negative_zero/output.css
+<===> up/negative_zero/output.css
 a {
   b: calc(-infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/nearest/negative_zero/input.scss
-@use "sass:math" as math;
+<===> nearest/negative_zero/input.scss
+@use "sass:math";
 a {b: math.div(1, round(nearest, -10, infinity))}
 
-<===> preserved/nearest/negative_zero/output.css
+<===> nearest/negative_zero/output.css
 a {
   b: calc(-infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/down/negative_zero/input.scss
-@use "sass:math" as math;
+<===> down/negative_zero/input.scss
+@use "sass:math";
 a {b: math.div(1, round(down, -0, infinity))}
 
-<===> preserved/down/negative_zero/output.css
+<===> down/negative_zero/output.css
 a {
   b: calc(-infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/positive/input.scss
-@use "sass:math" as math;
+<===> operation/positive/input.scss
 a {b: round(up, 10, infinity)}
 
-<===> preserved/operation/positive/output.css
+<===> operation/positive/output.css
 a {
   b: calc(infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/negative/input.scss
-@use "sass:math" as math;
+<===> operation/negative/input.scss
+@use "sass:math";
 a {b: round(down, -10, infinity)}
 
-<===> preserved/operation/negative/output.css
+<===> operation/negative/output.css
 a {
   b: calc(-infinity);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/one_arg/simplify/input.scss
+<===> operation/one_arg/simplify/input.scss
 a {b: round(3.8px + 4px)}
 
-<===> preserved/operation/one_arg/simplify/output.css
+<===> operation/one_arg/simplify/output.css
 a {
   b: 8px;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/two_args/simplify/input.scss
+<===> operation/two_args/simplify/input.scss
 $c: 10px;
 a {b: round(3.8px + 4px, $c)}
 
-<===> preserved/operation/two_args/simplify/output.css
+<===> operation/two_args/simplify/output.css
 a {
   b: 10px;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/two_args/math/input.scss
-a {b: round(3.4px + 10%, 1px + 4px)}
-
-<===> preserved/operation/two_args/math/output.css
-a {
-  b: round(3.4px + 10%, 5px);
-}
-
-<===>
-================================================================================
-<===> preserved/operation/nearest/math/input.scss
-a {b: round(nearest, 3.8px + 10%, 1.1px + 4px)}
-
-<===> preserved/operation/nearest/math/output.css
-a {
-  b: round(nearest, 3.8px + 10%, 5.1px);
-}
-
-<===>
-================================================================================
-<===> preserved/operation/nearest/simplify/input.scss
+<===> operation/nearest/simplify/input.scss
 a {b: round(nearest, 115px + 2px, 21px + 4px)}
 
-<===> preserved/operation/nearest/simplify/output.css
+<===> operation/nearest/simplify/output.css
 a {
   b: 125px;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/up/input.scss
+<===> operation/up/input.scss
 a {b: round(up, 101px, 25px)}
 
-<===> preserved/operation/up/output.css
+<===> operation/up/output.css
 a {
   b: 125px;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/down/input.scss
+<===> operation/down/input.scss
 a {b: round(down, 122px, 25px)}
 
-<===> preserved/operation/down/output.css
+<===> operation/down/output.css
 a {
   b: 100px;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/to-zero/positive/input.scss
+<===> operation/to-zero/positive/input.scss
 a {b: round(to-zero, 120px, 25px)}
 
-<===> preserved/operation/to-zero/positive/output.css
+<===> operation/to-zero/positive/output.css
 a {
   b: 100px;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/to-zero/negative/input.scss
+<===> operation/to-zero/negative/input.scss
 a {b: round(to-zero, -120px, 25px)}
 
-<===> preserved/operation/to-zero/negative/output.css
+<===> operation/to-zero/negative/output.css
 a {
   b: -100px;
 }
 
 <===>
 ================================================================================
-<===> preserved/infinity/input.scss
-@use "sass:math" as math;
+<===> nan/simplify/input.scss
+a {b: round(calc(NaN), calc(NaN))}
+
+<===> nan/simplify/output.css
+a {
+  b: calc(NaN);
+}
+
+<===>
+================================================================================
+<===> infinity/input.scss
+@use "sass:math";
 a {b: round(up, infinity, infinity)}
 
-<===> preserved/infinity/output.css
+<===> infinity/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/variable/one_arg/input.scss
-$a: 12.1;
-c {d: round($a)}
+<===> variable/one_arg/input.scss
+c {d: round($number: 12.1)}
 
-<===> preserved/variable/one_arg/output.css
+<===> variable/one_arg/output.css
 c {
   d: 12;
 }
 
 <===>
 ================================================================================
-<===> variables/input.scss
+<===> unknown_variable/one_arg/input.scss
 a {
+  --example: 5;
   b: round(var(--example));
-  c: round(up, var(--example));
-  d: round(up, 8px, var(--example));
 }
-<===> variables/output.css
+<===> unknown_variable/one_arg/output.css
 a {
+  --example: 5;
   b: round(var(--example));
+}
+
+<===>
+================================================================================
+<===> unknown_variable/two_args/second_arg/input.scss
+a {
   c: round(up, var(--example));
+}
+<===> unknown_variable/two_args/second_arg/output.css
+a {
+  c: round(up, var(--example));
+}
+
+<===>
+================================================================================
+<===> unknown_variable/three_args/first_arg/input.scss
+a {
+  e: round(var(--example), 8px, 9px);
+}
+<===> unknown_variable/three_args/first_arg/output.css
+a {
+  e: round(var(--example), 8px, 9px);
+}
+
+<===>
+================================================================================
+<===> unknown_variable/three_args/third_arg/input.scss
+a {
+  d: round(up, 8px, var(--example));
+}
+<===> unknown_variable/three_args/third_arg/output.css
+a {
   d: round(up, 8px, var(--example));
 }
 
diff --git a/spec/values/calculation/sign.hrx b/spec/values/calculation/sign.hrx
index 04cf30a81..0ae6039f4 100644
--- a/spec/values/calculation/sign.hrx
+++ b/spec/values/calculation/sign.hrx
@@ -5,28 +5,28 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> error/syntax/no_arg/input.scss
-a {b: calc(sign())}
+a {b: sign()}
 
 <===> error/syntax/no_arg/error
 Error: Expected number, variable, function, or calculation.
   ,
-1 | a {b: calc(sign())}
-  |                 ^
+1 | a {b: sign()}
+  |            ^
   '
-  input.scss 1:17  root stylesheet
+  input.scss 1:12  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/many_args/input.scss
-a {b: calc(sign(3, 2))}
+a {b: sign(3, 2)}
 
 <===> error/syntax/many_args/error
 Error: expected "+", "-", "*", "/", or ")".
   ,
-1 | a {b: calc(sign(3, 2))}
-  |                  ^
+1 | a {b: sign(3, 2)}
+  |             ^
   '
-  input.scss 1:18  root stylesheet
+  input.scss 1:13  root stylesheet
 
 <===>
 ================================================================================
@@ -44,15 +44,15 @@ Error: 1 and 16px are incompatible.
 <===>
 ================================================================================
 <===> error/syntax/invalid_arg/input.scss
-a {b: calc(sign($))}
+a {b: sign($)}
 
 <===> error/syntax/invalid_arg/error
 Error: Expected identifier.
   ,
-1 | a {b: calc(sign($))}
-  |                  ^
+1 | a {b: sign($)}
+  |             ^
   '
-  input.scss 1:18  root stylesheet
+  input.scss 1:13  root stylesheet
 
 <===>
 ================================================================================
@@ -67,7 +67,7 @@ a {
 <===>
 ================================================================================
 <===> error/unit/input.scss
-a {b: calc(sign(5%))}
+a {b: sign(5%)}
 
 <===> error/unit/output.css
 a {
@@ -76,50 +76,50 @@ a {
 
 <===>
 ================================================================================
-<===> preserved/operation/unit/positive/input.scss
+<===> operation/unit/positive/input.scss
 a {b: sign(5px)}
 
-<===> preserved/operation/unit/positive/output.css
+<===> operation/unit/positive/output.css
 a {
   b: 1;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/negative/input.scss
+<===> operation/unitless/negative/input.scss
 a {b: sign(-1000.65)}
 
-<===> preserved/operation/unitless/negative/output.css
+<===> operation/unitless/negative/output.css
 a {
   b: -1;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/zero/positive/input.scss
-a {b: sign(0)}
+<===> operation/zero/positive/input.scss
+a {b: sign(0px)}
 
-<===> preserved/operation/zero/positive/output.css
+<===> operation/zero/positive/output.css
 a {
   b: 0;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/zero/negative/input.scss
+<===> operation/zero/negative/input.scss
 a {b: sign(-0)}
 
-<===> preserved/operation/zero/negative/output.css
+<===> operation/zero/negative/output.css
 a {
   b: 0;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/nan/input.scss
+<===> operation/nan/input.scss
 a {b: sign(NaN)}
 
-<===> preserved/operation/nan/output.css
+<===> operation/nan/output.css
 a {
   b: calc(NaN);
 }
@@ -137,3 +137,39 @@ a {
   --one-arg: 2;
   b: sign(var(--one-arg));
 }
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: sign(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: sign(test);
+}
+
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: sign(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: sign(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: sign(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: sign(2px + var(--test));
+}
diff --git a/spec/values/calculation/sin.hrx b/spec/values/calculation/sin.hrx
index 5a4452207..593ecd07d 100644
--- a/spec/values/calculation/sin.hrx
+++ b/spec/values/calculation/sin.hrx
@@ -5,7 +5,7 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> negative_infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: sin(math.div(-1, 0))}
 
 <===> negative_infinity/output.css
@@ -16,7 +16,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: sin(math.div(1, 0))}
 
 <===> infinity/output.css
@@ -135,6 +135,44 @@ a {
   b: 0.8414709848;
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: sin(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: sin(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: sin(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: sin(2px + var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: sin(var(--test));
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: sin(var(--test));
+}
+
 <===>
 ================================================================================
 <===> error/type/input.scss
diff --git a/spec/values/calculation/sqrt.hrx b/spec/values/calculation/sqrt.hrx
index 496ae2c99..099360a6c 100644
--- a/spec/values/calculation/sqrt.hrx
+++ b/spec/values/calculation/sqrt.hrx
@@ -5,108 +5,108 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> error/syntax/no_arg/input.scss
-a {b: calc(sqrt())}
+a {b: sqrt()}
 
 <===> error/syntax/no_arg/error
 Error: Expected number, variable, function, or calculation.
   ,
-1 | a {b: calc(sqrt())}
-  |                 ^
+1 | a {b: sqrt()}
+  |            ^
   '
-  input.scss 1:17  root stylesheet
+  input.scss 1:12  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/operation_no_units/input.scss
-a {b: calc(sqrt(1 + 16px))}
+a {b: sqrt(1 + 16px)}
 
 <===> error/syntax/operation_no_units/error
 Error: 1 and 16px are incompatible.
   ,
-1 | a {b: calc(sqrt(1 + 16px))}
-  |                 ^^^^^^^^
+1 | a {b: sqrt(1 + 16px)}
+  |            ^^^^^^^^
   '
-  input.scss 1:17  root stylesheet
+  input.scss 1:12  root stylesheet
 
 <===>
 ================================================================================
 <===> error/syntax/invalid_arg/input.scss
-a {b: calc(sqrt($))}
+a {b: sqrt($)}
 
 <===> error/syntax/invalid_arg/error
 Error: Expected identifier.
   ,
-1 | a {b: calc(sqrt($))}
-  |                  ^
+1 | a {b: sqrt($)}
+  |             ^
   '
-  input.scss 1:18  root stylesheet
+  input.scss 1:13  root stylesheet
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/result_is_integer/input.scss
+<===> operation/unitless/result_is_integer/input.scss
 a {b: sqrt(16)}
 
-<===> preserved/operation/unitless/result_is_integer/output.css
+<===> operation/unitless/result_is_integer/output.css
 a {
   b: 4;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/result_is_float/input.scss
+<===> operation/unitless/result_is_float/input.scss
 a {b: sqrt(2)}
 
-<===> preserved/operation/unitless/result_is_float/output.css
+<===> operation/unitless/result_is_float/output.css
 a {
   b: 1.4142135624;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/unitless/negative/input.scss
+<===> operation/unitless/negative/input.scss
 a {b: sqrt(-9)}
 
-<===> preserved/operation/unitless/negative/output.css
+<===> operation/unitless/negative/output.css
 a {
   b: calc(NaN);
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math_nested/minus/input.scss
+<===> operation/math_nested/minus/input.scss
 a {b: calc(sqrt(10 - 1))}
 
-<===> preserved/operation/math_nested/minus/output.css
+<===> operation/math_nested/minus/output.css
 a {
   b: 3;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math/plus/input.scss
+<===> operation/math/plus/input.scss
 a {b: sqrt(10 + 6)}
 
-<===> preserved/operation/math/plus/output.css
+<===> operation/math/plus/output.css
 a {
   b: 4;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math/max/input.scss
+<===> operation/math/max/input.scss
 a {b: sqrt(max(2, 9))}
 
-<===> preserved/operation/math/max/output.css
+<===> operation/math/max/output.css
 a {
   b: 3;
 }
 
 <===>
 ================================================================================
-<===> preserved/operation/math/min/input.scss
+<===> operation/math/min/input.scss
 a {b: sqrt(min(16, 9))}
 
-<===> preserved/operation/math/min/output.css
+<===> operation/math/min/output.css
 a {
   b: 3;
 }
@@ -121,13 +121,51 @@ a {
   b: sqrt(5%);
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: sqrt(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: sqrt(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: sqrt(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: sqrt(2px + var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: sqrt(var(--test));
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: sqrt(var(--test));
+}
+
 <===>
 ================================================================================
 <===> syntax/units/input.scss
 a {b: calc(sqrt(16px))}
 
 <===> syntax/units/error
-Error: Expected 16px to have no units.
+Error: $number: Expected 16px to have no units.
   ,
 1 | a {b: calc(sqrt(16px))}
   |            ^^^^^^^^^^
@@ -140,7 +178,7 @@ Error: Expected 16px to have no units.
 a {b: calc(sqrt(min(16, 9px)))}
 
 <===> syntax/min_units/error
-Error: Expected 9px to have no units.
+Error: $number: Expected 9px to have no units.
   ,
 1 | a {b: calc(sqrt(min(16, 9px)))}
   |            ^^^^^^^^^^^^^^^^^^
diff --git a/spec/values/calculation/tan.hrx b/spec/values/calculation/tan.hrx
index 47b2f04be..868690ab3 100644
--- a/spec/values/calculation/tan.hrx
+++ b/spec/values/calculation/tan.hrx
@@ -5,7 +5,7 @@ terseness' sake isn't tested explicitly.
 <===>
 ================================================================================
 <===> negative_infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: tan(math.div(-1, 0))}
 
 <===> negative_infinity/output.css
@@ -16,7 +16,7 @@ a {
 <===>
 ================================================================================
 <===> infinity/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: tan(math.div(1, 0))}
 
 <===> infinity/output.css
@@ -27,7 +27,7 @@ a {
 <===>
 ================================================================================
 <===> negative_asymptote/radian/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: tan(-0.5rad * math.$pi)}
 
 <===> negative_asymptote/radian/output.css
@@ -38,7 +38,7 @@ a {
 <===>
 ================================================================================
 <===> asymptote/radian/input.scss
-@use "sass:math" as math;
+@use "sass:math";
 a {b: tan(0.5rad * math.$pi)}
 
 <===> asymptote/radian/output.css
@@ -157,6 +157,56 @@ a {
   b: 1.5574077247;
 }
 
+<===>
+================================================================================
+<===> preserved/percent/input.scss
+a {b: tan(3px - 1.5px + 5%)}
+
+<===> preserved/percent/output.css
+a {
+  b: tan(1.5px + 5%);
+}
+
+<===>
+================================================================================
+<===> preserved/operation/variable/input.scss
+a {
+  --test: 5;
+  b: tan(3px - 1px + var(--test));
+}
+
+<===> preserved/operation/variable/output.css
+a {
+  --test: 5;
+  b: tan(2px + var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/variable/input.scss
+a {
+  --test: 5;
+  b: tan(var(--test));
+}
+
+<===> preserved/variable/output.css
+a {
+  --test: 5;
+  b: tan(var(--test));
+}
+
+<===>
+================================================================================
+<===> preserved/unquoted_string/input.scss
+a {
+  b: tan(test);
+}
+
+<===> preserved/unquoted_string/output.css
+a {
+  b: tan(test);
+}
+
 <===>
 ================================================================================
 <===> error/type/input.scss