How many 6 permutations sets are there of the set {5, 6, 7, ..., 18}?

Answer 1

14 choices for the 1st item,
13 for the 2nd,
12 for the 3rd,
11 for the 4th,
10 for the 5th, and
9 for the 6th.

14 x 13 x 12 x 11 x 10 x 9

2,162,160 ways to arrange 6 items from a set of 14 items. You said "permutation" so order matters.