Lesson 2B: Factorials

In Lesson 2A you were introduced to counting problems. You learned how to use sample space to solve these problems, but discovered that the Fundamental Counting Principle is often more efficient. When working with this principle, you may have noticed that the solution to a counting problem often involves strings of numbers multiplied together. The following scenario will explore this further.

The picture below shows four beach volleyball players who want to choose starting positions for their team. The diagram shows the four starting positions that team members can take. If you want to determine how many starting formations are possible for the four players, use the Fundamental Counting Principle.

There are 24 starting formations for the players on this beach volleyball team.

The total number of possible outcomes for the volleyball scenario was determined by multiplying 4 × 3 × 2 × 1. This string of numbers can be expressed in a more efficient way using factorial notation . You will learn about factorial notation in this Training Camp .

By the end of this lesson, you should be able to

	determine, with or without technology, the value of a factorial
	simplify a numeric or an algebraic fraction that contains factorials in both the numerator and denominator
	solve an equation that involves factorials