Combinatorial calculator

Find out how many different ways you can choose k items from n items set. With/without repetition, with/without order.

(n)
(k)

Calculation:

C_k(n) = {n  choose k} =  frac{ n! }{ k! (n-k)!} $    $ C_{{ 4}}(10) = {{ 10}  choose 4} =  frac{ 10! }{ 4!(10-4)!}  =  frac{ 10  * 9  * 8  * 7 } { 4  * 3  * 2 }  = 210 $    $

Number of combinations: 210