Combinations without repetition

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} = fraction{ n! }{ k! (n-k)!}; C_{{ 2}}(24) = {{ 24} choose 2} = fraction{ 24! }{ 2!(24-2)!} = fraction{ 24 * 23 } { 2 * 1 } = 276

Number of combinations: 276