Disclaimer: Some of these are so bad that they physically *hurt*, but I suppose I'll post them in the interest of sadism.
Mathematic puns are the first sine of madness.
Why do mathematicians confuse halloween and christmas? Because 31 Oct = 25 Dec!
A student was found dead in a lecture theatre, the blackboard covered in Calculus. The police arrived, took away the body and performed an autopsy. The student's lecturer went to ask how the student had died. The police told him that the boy's blood alchol level had been quite high. Confused, the lecturer asked how this had led to the boy's death. The policeman responded:
"Don't you know never to drink and derive?"
When the flood ended, Noah opened the ark and said "go forth and multiply". A couple of days after, Noah went out into the forest, and found that all of the animals had multiplied, except for particular breed of dark snakes. When Noah asked the two snakes why they hadn't reproduced, they told him to chop down some trees and return in a few weeks. Noah obliged, and returned a month later, to find the forest brimming with the snakes. Curious, Noah asked, "Why did the trees help you to reproduce?". The snakes replied, "We're Adders, we need logs to multiply!".
Chat up lines:
1. Are you the square root of 2, 'cause you're making me irrational!
2. <insert something involving exponent curves>