Here's some good math jokes.

Q: Why do they never serve beer at a math party? A: Because you can't drink and derive... Q: Why didn't the quarter roll down the hill with the nickel? A: Because it had more cents. Q: Did you hear about the constipated mathematician? A: He worked it out with a pencil. Q: How many molecules in a bowl of guacamole? A: Avacado's Number Q: What happened to the plant in math class? A: It grew square roots. Q: Why did the chicken cross the mobius strip? A: To get to the same side. Q: How do you make seven an even number? A: Take the s out! Q: Why should the number 288 never be mentioned? A: It's two gross. Q: Why couldn't the moebius strip enroll at the school? A: They required an orientation. Q: What does a mathematician do about constipation? A: He works it out with a pencil. Q: Why is a math book always unhappy? A: Because it always has lots of problems. Q: Why don't you do arithmetic in the jungle? A: Because if you add 4+4 you get ate! Q: Why did I divide sin by tan? A: Just cos. Q: Where do math teachers go on vacation? A: To Times Square. Q: Why is 6 afraid of 7? A: Because 7 8 9 Q: What does the zero say to the the eight? A: Nice belt! Q: Why did the mutually exclusive events break up? A: They had nothing in common. Q: How is an artificial christmas tree like the fourth root of -68? A: Neither has real roots.

source: http://www.jokes4us.com/miscellaneousjokes/mathjokes/