# I am not understanding: C[4],[3] times C[48],[2]

#### Corkylr1270

##### New member
I am trying to understand my homework. The problem is this
Find the probability of having exactly three kings when dealing five cards from a standard deck of 52 cards.
so from looking at other examples i know i need to do this

C [4],[3] x C [48],[2] these are subscripts

I understand that this means I need 3 out of the 4 Kings, and any 2 of the other 48 cards.
I am not understanding how to do this math though. From looking at examples C4,3= 4. I know that this is because there are 4 ways to get 3 kings, but i don't understand the math and 2 of 48 is too difficut to try writing all pairs out.

#### royhaas

##### Full Member
Re: I am not understanding...

$$\displaystyle C(n,m) = \frac{n!}{m!(n-m)!}$$.