How many combinations of 4 spades can be pulled from the 13 spades in a standard deck of cards?
Think about the effect of taking one card at a time from the 13 spades.
There are 13 different options for the first spade.
Once one is drawn, there are 12 left to choose from.
Once two are drawn, there are 11 left to choose from.
Once three are drawn there are 10 left to choose from.
The total number of combinations is