1. What does the B in Benoît B. Mandelbrot stand for?
2. There are 10 kinds of people in this world.
3. Why do mathematicians confuse Halloween and Christmas?
5. What's purple and commutes?
7. What's the integral of 1/cabin with respect to cabin?
8. What's an anagram of Banach-Tarski?
9. An infinite number of mathematicians walk into a bar. The first orders a beer, the second orders half a beer, the third orders a quarter of a beer and so on.
10. A museum visitor was admiring a Tyrannosaurus fossil, and asked a nearby museum employee how old it was.
12. What do you get if you cross an elephant and a banana?
13. Why did the chicken cross the Möbius strip?
14. Let epsilon be less than zero.
16. How many mathematicians does it take to screw in a lightbulb?
18. I was dating this topologist once, but we got into an argument over a coffee mug...
19. Why aren't jokes in base 8 funny?
20. What's the difference between an introverted and extroverted mathematician?
21. What is non-orientable and lives in the ocean?
This post has been updated to meet attribution standards.