## Operating on numbers, colors, and variables

*Less* has support for the basic arithmetic operations: addition (`+`

), subtraction (`-`

), multiplication (`*`

), and division (`/`

). In the strict-math mode, operations should be placed between parentheses. You can apply an operation on variables, values, and numbers. These will help you make relationships between variables.

Open `less/footer.less`

to immediately see the operation that you used, as in the following code, and its benefits:

footer { div { float: left; width: ((@basic-width / 3 ) - @footer-gutter); } }

In the preceding code, the `/`

sign (division) has been used to give the footer columns one-third of the available width (as set by `@basic-width`

). Using operations in your code feels so natural that you may not have even realized you have been using them until now. *Less* uses normal **order precedence**, where you can add extra parentheses to explicitly set precedence and avoid confusion. For instance, in *Less*, *3 + 3 * 3* gives *12*. So, *(3 + 3)...*