# Very slow with maths.

#### Andy

Using “Only Four” ZEROS (0) and any Mathematical Operations/Symbols, to obtain the number 24.
So can someone explain to me how, (0! + 0! + 0! + 0!)! = 24

Im sure this is simple to most of you but i am very slow when it comes to maths.

#### goo

I still don't get it. Can someone explain?

4! = 4 x 3 x 2 x 1 = 24

0! = 0 x -1 x -2 x -3 ~ = 1

huh? :)

#### Guybrush Threepwood

no 0! = 1 (by definition)
you can think of it like this:
n! = (n-1)!*n
so:
3! = 2!*3
2! = 1!*2
1! = 0!*1 => 0! = 1

also there is no factorial for negative or not-integer numbers (at least I think...)

#### Guybrush Threepwood

well it seems there is possible to define factorial for complex numbers:
factorial from mathworld

#### goo

thanks guybrush, that cleared things up.

Thank you.

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