SOLUTION: how many ways can you choose 2 stamps out of 7

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Question 732503: how many ways can you choose 2 stamps out of 7
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
here you need to use combinations, the items do not have to be in any particular order, just rearrange them in the same sequence

nCr=n%21%2F%28n-r%29%21r%21

7C2=7%21%2F%287-2%29%212%21

7C2=7%21%2F%285%212%21%29

7C2=5040%2F%28120%2A2%29

7C2=5040%2F240

7C2=21