There are three signs of senility. The first sign is that a man forgets his theorems. The second sign is that he forgets to zip up. The third sign is that he forgets to zip down.
Television is something the Russians invented to destroy American education.
I know numbers are beautiful. If they aren't beautiful, nothing is.
Another roof, another proof.
I'll tell you once, and I'll tell you again. There's always a prime between n and 2n.
Property is a nuisance.