how many possible ways of 3 items from a group of 7 are possible math

Question

how many possible ways of 3 items from a group of 7 are possible

Answer 1

If the order of the items taken matters, there are 7 possibilities for the first, 6 for the second and 5 for the third for 7*6*5=210 possibilities. If order does not matter, those 210 possibilities are reduced by 3*2*1 or 6 so there are 210/6 = 35 possibilities.

The first scenario is referred to as a permutation without repetition and the general equation for taking r objects from a group of n is n!/(n-r)!

The second scenario is referred to as a combination without repetition and its equation is n!/r!(n-r)!