Counting principle

Key Notes:

✈️ The Counting Principle says that you can multiply the number of choices to find the total number of possibilities.

Learn with an example

🎯 Roy is building a playground. There are 5 different slides and 2 swing sets to choose from. If the playground will include one of each type of play structure,

how many different playgrounds can Roy build?

______ playgrounds

  • There are 5 slide choices and 2 swing set choices. Multiply.
  • 5 × 2 = 10
    Roy can build 10 different playgrounds.

🎯 Brenna is a reporter for the college newspaper and is writing an article about the American football team. Brenna wants to interview one freshman and one sophomore on the American football team, and there are 4 freshmen and 4 sophomores to choose from.

How many different sets of people can Brenna interview?

_______ sets

  • There are 4 freshman choices and 4 sophomore choices. Multiply.
  • 4 × 4 = 16
    Brenna can interview 16 different sets of people.

🎯 Kelsey is going out to a pasta dinner. There are 3 types of noodles to choose from and 2 choices of vegetable side.

How many different pasta dinners can Kelsey order?

______ pasta dinners

  • There are 3 noodle choices and 2 vegetable side choices. Multiply.
  • 3 × 2 = 6
  • Kelsey can order 6 different pasta dinners.

Let’s practice!🖊️