The multiplication counting principle states that there are n ways to order n things.
Counting More than One Item
If there are m ways to make a first selection and n ways to make a second selection, there are m
× n ways to make the two selections.
Consider the following example: For lunch you can eat either a turkey sandwich, a cheeseburger or a slice of pizza so you have three choices for your main meal. Then for dessert, you can have either grapes or cookies, 2 choices. By the multiplication counting principle we know there are a total of 3×2 ways to have your lunch and dessert.
3×2 = 6 different, possible ways
1) sandwich & grapes 2) sandwich & cookies
3) burger & grapes 4) burger & cookies
5) pizza & grapes 6) pizza & cookies