Question

determine the number of permutation of 18 items taken 5 at a time.

Answer 1

18 chooses 5 = 1028160?

Answer 2

ok thanks :)

Answer 3

np

Answer 4

I though the phase "18 choose 5" usually refers to combinations not permutations.
Combinations:
\[18C5 = \frac{18!}{5!(18-5)!}\]
Permutations:

\[18P5 = \frac{18!}{(18-5)!}\]