An infinite number of mathematicians walk into a bar. The first one orders a beer. The second one orders half a beer. The third one orders a fourth of a beer. The bartender stops them, pours two beers and says, "You guys should know your limits."

An chemist, a physicist, and a mathematician are stranded on an island when a can of food rolls ashore. The chemist and the physicist come up with many ingenious ways to open the can. Then suddenly the mathematician gets a bright idea: "Assume we have a can opener..."

A mathematician stumbles home drunk at 3 a.m. and his wife is livid. "You swore that you'd be home by 11:45!" "No," slurs the mathematician, "I said I'd be home by a quarter of 12."