What+is+a+factorial?+How+do+you+solve+these+types+of+problems?

What is a factorial?

A factorial is when you multiply a number by all the natural numbers after it. It's written //n//!. This means to multiply //n// by all the natural numbers above zero after it. If //n// was 5, you would multiply 5*4*3*2*1. This is pronounced "5 factorial", but is also known as "5 shriek" or "5 bang".

How do you solve these types of promblems?

To solve a factorial, multiply that number by all the natural numbers above zero after it.

Examples: 1!=11 2!=2*1, or 2 3!=3*2*1, or 6 4!=4*3*2*1, or 24 etc., etc.

If you already know 4!, but need to find 5!, you could just say that 5!=5*4!. So, n!=n*(n-1).

** *http://www.purplemath.com/modules/factorial.htm **

 * by: alexis amelie **