ProofWiki:Jokes

0.999...=1

 * Q: How many mathematicians does it take to change a lightbulb?
 * A: 0.999999 ...

Banach-Tarski Paradox

 * Q: Give me an anagram of Banach-Tarski.
 * A: Banach-Tarski Banach-Tarski.

Educational Standards
Two captains of industry, Arthur and George, were in a restaurant discussing the state of educational standards, particularly in the field of mathematics. Arthur was convinced they were slipping badly, and that your average college student was completely mathematically illiterate. George, on the other hand, was confident that any student would at least know the basics of calculus.

"I bet you twenty bucks," said Arthur, "that if you were to ask a random college student a basic question in calculus, he wouldn't understand the question, let alone furnish you with an answer."

"I'll think about that," said George. "Not sure whether to take you up on your bet or not, but I reckon you'd be wrong."

Arthur slipped off to the mens' room at that point, and while he was gone, George called over the waitress Jody.

"I'd like you to help settle a wager between me and my colleague," he said. "When he comes back, I'm going to call you over, and ask you a question, to which you are to answer: one third x cubed."

"Wuntur dex cue?"

"One third x cubed."

"One thurrd ex cuebd."

"That's it, one third x cubed."

"One third ... x cubed."

"That's it, perfect. There's a good tip in it for you."

Arthur returned. George said, "Yes, I think I will take you up on it. Twenty bucks says our waitress can answer such a question. Hey, Jody! What's the indefinite integral of x squared with respect to x?"

"One third x cubed," replied Jody, dutifully.

"You see?" said George, pocketing Arthur's twenty.

As Jody turned away, she called back over her shoulder, "Plus a constant."

Knot Theory

 * Student A: "What's your favourite area of mathematics?"
 * Student B: "Knot theory."
 * Student A: "Me neither."

Natural Numbers

 * Q: "Why do computer scientists have nine fingers?"
 * A: "Zero, one, two, three, four; five, six, seven, eight, nine."