why is 0! = 1?

(By seeing these questions everyday i can answer it from CPhill's help)

I haven't got a proper answer to this but...

5! = 6!/6

4! = 5!/5

3! = 4!/4

2! = 3!/3

...

So,

0!= 1!/1

That's exactly the way I would have "proved" it too, MathsGod1 .....!!!!!

Very nice work  !!!!!

Excellent answer MG  :D