## Algebra 2 (1st Edition)

We know the following equation for permutations: $$nP_r=\frac{n!}{(n-r)!}$$ Thus, we find: $$nP_r=\frac{n!}{(n-0)!}=1$$ This makes sense because when $r$ is 0, there are 0 objects from the group, so there is only one way to organize them.