Yes, I'm Still Grading

Dear Calculus Students,

The prohibition against division by zero is not some sort of moral advice, like sex before marriage or swearing in front of women and children or crossing the street before looking both ways or taking the square root of a negative number. It's not that you shouldn't divide by zero; it's that you can't.

Believe you me, if we could divide by zero, I wouldn't have spent a week trying to teach you about limits.