Reminds me of one a professor told in class. Lemme see if I can do it justice; it was 15 years ago. A math professor's friend is visiting from out of town, and

Reminds me of one a professor told in class. Lemme see if I can do it justice; it was 15 years ago. A math professor's friend is visiting from out of town, and they go out to dinner. The professor says that in this town, everyone has a college degree and knows calculus. He makes a bet with his friend that the waitress can solve an integral. But there's no way waitstaff know calculus, so he cheats: he excuses himself to go to the bathroom, finds the waitress, and tells her that when he asks her a question, she should answer "x^2 / 2". Then he goes back to the table. When the waitress checks on them, he asks her "what's the integral of x"? She answers "x^2 / 2 plus an arbitrary constant".