Not much. I do use quick-and-dirty basic math at the store, as #4 says, for coupons and per-item cost, but I usually use the calculator in my phone for anything more substantial than base costs. At work, the computer calculates change for me, and the other parts of work have no math involved at all. Out of work, I mostly have access to at least a basic calculator.
So no, I don't use much math at all. However, others pick it up faster and I would advise anyone with a head for math to learn it; it comes in handy when you least expect it.