Is it possible to use calc() to multiply or divide with unit-based values (like 100%, 5px, etc).
For example I was hoping to do something like this:
width: calc(100% * (.7 - 120px / 100%));
width: calc(500px * (.7 - 120px / 500px));
width: calc(500px * (.7 - .24));
width: calc(500px * .46);
5px * 10px
5px * 100%
In CSS calc() division - the right side must be a
<number> therefore unit based values cannot be used in division like this.
Also note that in multiplication at least one of the arguments must be a number.
The MDN has great documentation on this.
If you'd like a better way to do calculations you can use a preprocessor (I like Sass). That like will take you to their guides (on that page there's a section about operators).