So what's the idea, concept of '0! = 1'

[FedPete]

‘0’ is a number, it’s to describe there is no value.
So why is 0! = 1.
Is there a (short) answer, or it’s just a rule to make it work?

edit: found this answer online… http://mathforum.org/dr.math/faq/faq.0factorial.html

[garypettie]

Hi @FedPete,
That link you found I think answers it fairly well.
the way I look at it is the same as their first example of completing the pattern, so;

n! = (n - 1)! / (n - 1)

So for 0!, this gives us;

0! = 1! / 1 = 1

[FedPete]

Thanks, it’s because of my no math brain. Trained to work from A to B to C …
It’s intriguing to learn, that sometimes reasoning backwards, can result in a solution, like starting value as in 0! = 1! / 1 = 1

Still having fun!