Birthday is good for prolonging life, because statistics show that people who live longer have more birthdays.

Q: What is purple and exchangeable?

A: An Abel grape. (Abel grapes. Abel group is interchangeable, while grape group and grape group are similar in shape.

Q: What is it that Zi and her descendants are all devoted to academics?

A: Simple grapes: It has no normal grapes. A simple grape. It has no normal grapes (normal subgroup). )

Q: What is an additive, closed, combined, distributed Abelian group with a terrible curse?

A: The Ring of Nibelungen. (The "ring" is an Abelian group that meets the above characteristics ... the Nibelungen ring is cursed ...)

Q: What do you get by crossing an elephant with a banana?

Answer: | Elephant | *| Banana | * sin(θ). [Well, the cross represents vector multiplication]

Q: What is black and white and can fill the whole space?

A: Piano curve. (peano curve/Piano Curve. Don't bother when you're dead. )

Q: How many digits does it take to change a light bulb?

A: It has not been proved, but we guess it must be an excellent prime number.

Q: How many analysts does it take to change a light bulb?

A: Three. One proves the existence, the other proves the uniqueness, and the third deduces a non-structural algorithm to realize it.

Q: How many light bulbs does it take to change a light bulb?

A: One, as long as it knows its Godel number.