The value of

${ }^{n} P_{r} \div{ }^{n} C_{r}=\frac{{ }^{n} P_{r}}{{ }^{n} C_{r}}$

$=\frac{n !}{(n-r) !} \times \frac{(n-r) ! r !}{n !}$

Therefore, ${ }^{n} P_{r} \div{ }^{n} C_{r}=r$