Topics

  • Addition Principle: If there are m ways to do one thing and n ways to do another (and they are mutually exclusive), there are m + n ways to do either.
  • Multiplication Principle: If there are m ways to do one thing and n ways to do another (independent events), there are m * n ways to do both.

Example

How many ways are there to choose a topping for your pizza if you have 3 choices of crust and 5 choices of toppings? (3 * 5 = 15)