There are 10 people on a team. 5 are chosen. which expression gives number of ways

The number of ways in this case will involve computation of number of combinations available. That is,
Number of ways to select 5 = Total number C Number to be chosen. Where "C" stands for combination

Substituting;
Number of ways to select 5 from 10 people = 10C5 = 10!/{5!*(10-5)!} = 10!/(5!*5!) = 252 ways