Question

Why 0 factorial equal to 1​

Answer 1

you can see the factorial as many different ways, i will only show you two

• first way

you can see
`n!=((n+1)!)/(n+1)`

so 0! would mean that

`0!=((0+1)!)/(0+1)=(1!)/(1) =1/1=1`

• second way

the other way you can see factorial is as the number of ways to order n things

let's say we have

a b and c and we want to arrange them in all possible ways so those are

abc

acb

bac

bca

cab

cba

and no more

for just a and b

we have

ab

ba

and no more

for just a

we have only

a

for no objects we have

that way, the one that it's upward, it's a bit philosophical but i hope you understand it

Answer 2

This still counts as a way of arranging it, so by definition, a zero factorial is equal to one, just as 1! is equal to one because there is only a single possible arrangement of this data set