Answer
$800$
Work Step by Step
Factorial Notation
$n!=n(n-1)(n-2)\cdots(3)(2)(1) $ and $0!=1 $(by definition)
It follows that $n!=n(n-1)!$
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$\displaystyle \frac{800!}{799!}=\frac{800(799!)}{799!}\qquad$ ... reduce the fraction (divide with $\displaystyle \frac{799!}{799!}$)
$=800$
