Brows­ing through the Wikipedia entry for math­e­mat­i­cal jokes, I noticed a ref­er­ence to the intrigu­ingly titled Fool­proof: A Sam­pling of Math­e­mat­i­cal Folk Humor (pdf) that appeared in Notices of the Amer­i­can Math­e­mat­i­cal Soci­ety back in 2004.

Many English-language math­e­mat­i­cal jokes are based on word play involv­ing stan­dard math­e­mat­i­cal con­cepts and ter­mi­nol­ogy. In fact, many of the jokes involve food items, which may be a reflec­tion of the fact that some math­e­mat­i­cal con­cepts are hard to digest, or dif­fi­cult to swallow:

Q: What’s pur­ple and com­mutes?
A: An abelian grape.