[beejiu]

From my experience of professional mathematicians at university, arithmetic was usually their worst skill. They'd quite often struggle (for a short moment) to multiply, say, 12 and 16 together. The public perception of a mathematician is somebody who remembers Pi to a 1,000 digits. A real mathematician doesn't care less.

[lostcolony]

This. So much this. Arithmetic is bookkeeping, it's turning an elegant abstract process into an ugly solved instance through rote mechanical labor.

In most of my college math classes, I largely 'got' it, but what killed me, and many other students, was the arithmetic. We could take multiple integrals, but dammit, 2*3 /= 5. Thank God for partial credit.