## Thinking Mathematically (6th Edition)

The number of possible permutations if r objects are taken from n itself is: nPr = $\frac{n!}{(n-r)!}$ The number of different ways you can arrange the photographs, assuming that the order of the pictures makes a difference to you, is: 10P10 = $\frac{10!}{(10-10)!}$ = 3628800 ways