I don't know about you, and your mathematics education background, but by the time I took my various math classes in university (I was in faculty of math), the

I don't know about you, and your mathematics education background, but by the time I took my various math classes in university (I was in faculty of math), the higher level the classes, the less often I see numbers. People seem to associate "mathematicians" with "wizardry in arithmetics," but even before I finish undergrad, I understand "1 + 1" doesn't necessarily have to be 2. That's how mathematicians think (at least those who are interested in rings, fields, etc). That stupid 15% tip? It's child's play and has long since been delegated to calculators.