6. Combination of 9 pick 6

This seems easy but I am not sure how to set the problem up.

Thanks!

2 answers

9!/3!6!
C(9,6)
= 9!/(6!3!)
= 362880/(720 x 6)
= 84

you should have a C(n, r) key on you r calculator
sometimes shown as nCr
on mine it is found under the "5" key

so enter
9
nCr
6
=

to get 84