! is factorial
it means multipliy all numbers from 1 to that number together
example
1!=1
2!=2*1
3!=3*2*1
etc
some things to note
7!*8=8!
4!*5*6=6!
so we can rewrite it as
=
=
it means multipliy all numbers from 1 to that number together
example
1!=1
2!=2*1
3!=3*2*1
etc
some things to note
7!*8=8!
4!*5*6=6!
so we can rewrite it as