Factorial: Denoted by the exclamation mark (!). Factorial means to multiply by decreasing positive integers. For example, 5! = 5 ∗ 4 ∗ 3 ∗ 2 ∗ 1 = 120.

What does an exclamation point mean in an equation?

Factorials are very simple things. They're just products, indicated by an exclamation mark. For instance, "four factorial" is written as "4!" and means 1×2×3×4 = 24. In general, n! ("enn factorial") means the product of all the whole numbers from 1 to n; that is, n!

What does it mean if there is an exclamation point after a number?

The expression n! means "the product of the integers from 1 to n". For example, 4! (read four factorial) is 4 × 3 × 2 × 1 = 24.