why 0! = 1. Idk it seems counterintuitive.

Question

Title

In: Mathematics

Answer 1

There’s an easy proof for it that might help some people understand.

n! = (n+1)! / n+1

For example, if n = 3:

3! = 4! / 4 = 24 / 4 = 6

So 0! = 1! / 1 = 1 / 1 = 1