jmc

By definition $0!=1$. Thus, $\left(\genfrac{}{}{0ex}{}{n}{0}\right)=\frac{n!}{0!n!}=\boxed{1}$. Also, the only way to choose 0 objects out of $n$ is not to choose any of them, so $\left(\genfrac{}{}{0ex}{}{n}{0}\right)=\boxed{1}$.