Funny Math Jokes

As a former math major, I think these are all hilarious, but I'll only include two here and leave a review of the rest at the link as an exercise for the reader:

An engineer, a physicist and a mathematician are staying in a hotel. The engineer wakes up and smells smoke. He goes out into the hallway and sees a fire, so he fills a trash can from his room with water and douses the fire. He goes back to bed. Later, the physicist wakes up and smells smoke. He opens his door and sees a fire in the hallway. He walks down the hall to a fire hose and after calculating the flame velocity, distance, water pressure, trajectory, etc. extinguishes the fire with the minimum amount of water and energy needed. Later, the mathematician wakes up and smells smoke. He goes to the hall, sees the fire and then the fire hose. He thinks for a moment and then exclaims, "Ah, a solution exists!" and then goes back to bed.

A biologist, a physicist and a mathematician were sitting in a street cafe watching the crowd. Across the street they saw a man and a woman entering a building. Ten minutes they reappeared together with a third person.

- They have multiplied, said the biologist.

- Oh no, an error in measurement, the physicist sighed.

- If exactly one person enters the building now, it will be empty again, the mathematician concluded.

Hat tip: 4Gravitons.