Math Joke...I ache with hilarity.
Noah lands the Ark atop the mountain, lets down the ramp, and says to his animals, "Go forth and multiply!" And all the animals leave, two by two, into the forest, except for a pair of snakes. Upon questioning, the snakes say, "We can't multiply, we're adders." They leave anyway.
Later, Noah is taking a walk and trips, and falls flat on his face. He looks back to see what he tripped over, and he sees a log, and under it, the two adders with a bunch of baby adders. Noah exclaims, "But you said you could not multiply!" The snakes nod. "That's what we thought too, but then we found this log that lets us multiply by adding, and..."