Question

in how many ways can a coach select 5 players from a team of ten players

Answer 1

5C10 = 252

Answer 2

From 10 people, you have to choose 5. The answer to this commonly denoted by 10C5 (pronounced 10-choose-5) or \[\binom{10}{5}\]The formula for calculating this is given by \[{10! \over 5!(10-5)!}\]Which, as Jlastino pointed out, is equal to 252.