## Factorialfactorial is a number that is the result of multiplying a number by all the whole numbers below it. It is written with an exclamation mark (!) after it, like this:
Here are two examples: 5! = 5 x 4 x 3 x 2 x 1 = 120 6! = 6 x 5 x 4 x 3 x 2 x 1 = 720 Notice that if you divide 6! by 5! you get only the 6:
... because all the numbers in 5! cancel the same numbers in 6!
Now here are a couple of problems for you: What is 4!? _________ What is 5! / 2! ? __________ |