You need to ask yourself...
Does order matter? If it did this would be a permutation question.
In this case order does not matter, so it is a combination question
10Choose4
A student is given a reading list of ten books from which he must select four for an outside reading requirement. In how many ways can he make his selections?
2 answers
1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
1, 2, 3, 4.
2, 3, 4, 5.
3, 4. 5, 6.
4, 5, 6, 7.
5, 6, 7, 8.
6, 7, 8, 9.
7, 8, 9, 10.
8, 9, 10, 1.
9, 10, 1, 2.
10, 1, 2, 3.
There are 10 different ways.
1, 2, 3, 4.
2, 3, 4, 5.
3, 4. 5, 6.
4, 5, 6, 7.
5, 6, 7, 8.
6, 7, 8, 9.
7, 8, 9, 10.
8, 9, 10, 1.
9, 10, 1, 2.
10, 1, 2, 3.
There are 10 different ways.