In normal maths, we don't use binary. We were taught to use our normal number system. Binary is much easier to do math in than normal numbers because you only are using two symbols - 1 and 0 instead of ten symbols - 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Computers use binary because they can only read and store an on or off charge. So, using 0 as off and 1 as on, we can use numbers in electrical wiring.