#### Answer

factorial;
5;
1;
1

#### Work Step by Step

RECALL:
(1) $n!$, read as $n$ factorial, is defined by the formula:
$n!=n(n-1)(n-2)(n-3)...(3)(2)(1)$
where $n$ is a non-negative integer.
(2) $0! = 1$
Thus, $5!$ is 5 factorial. This is equal to the product of all positive integers 5, 4, 3, 2, and 1.
Therefore the missing expressions in the given statements are:
factorial;
5;
1;
1