SCSS: using calc with sass variables [duplicate]

This question already has an answer here:

• Sass Variable in CSS calc() function 1 answer

I need to do something similar using SCSS:

$aVariable: 100px;
width: calc(100% - $aVariable);

The compiler will complain that % and px are not compatible. Fair enough, but since native css can do it, is there a way in SCSS to simply output the contents of a variable instead of [trying] to perform the calculation;

Thanks in advance.