Computation theory, but that's not math as in regular math. It's just a fancy way of expressing how things inside a computer work, so we can actually make better versions of it. You just have to express it somehow in math terms.

It's like saying engineers use math all the time. No, they don't. We use simple aproximations of what is actually happening to dumb down the problem, cuz, it does the job nicely and no one will notice the difference between what we used, a simple aproximation, and the real thing, a full blown advanced calculus model of the thing we're working on.