Old mathematicians never die...
They just lose some of their functions.
When a neighbor's home was burglarized, I decided to be more safety conscious. But my measly front-door lock wasn’t going to stop anyone, so I hung this sign outside: "Nancy, don’t come in. The snake is loose. Mom."
How do you put a baby alien to bed?
You rocket to sleep.
What do you call a lazy kangaroo?
A pouch potato.