Simplifying Expression Factorial Expression I'm confused as how I'm meant to simplify this:$$\frac{(n-2)!}{(n-2-r)!}$$
I have other factorial questions where the variable isn't present in the top factorial like the question above and I'm trying to figure out how I simplify.
Thanks

As noted in the comments, here is a useful hint: 
If $r \geq 0$, then 
$$\frac{(n-2)!}{(n-2-r)!} = \frac{(n-2)(n-3) \dots (n-2-r + 1)(n-2-r)\dots (2)(1)}{(n-2-r)!}$$
If the $r$ in the expression makes it confusing, try letting $r$ equal a positive integer.  Say, $r = 2$.
