[TipRoast]

Here's the equation you want:

(n+r-1)!
-----------
r! * (n-1)!

In your case,

n (number from which to choose) = 4
r (number chosen) = 4

So the equation reduces to this:

7!
-------
4! * 3!


or

7*6*5 * 4!
-----------
4! * 3!

which is 35.