# Chapter 8: Combinations and Permutations

**At Grade**Created by: CK-12

The mathematics of combinations, “combinatorics”, is a study in it’s own right, but it is also an important part of the mathematics of probability. There are two basic divisions of combinatorics: *permutations*, which are groupings of items where the *order* of the items is important, and *combinations*, where only the *identity* of the items is important, regardless of the order in which they appear.

In this chapter, you will study both kinds of groupings, and you will learn to calculate the number of possible unique ways to combine or arrange items of all kinds.

## Chapter Outline

- 8.1. Combinations and Permutations
- 8.2. Calculating Permutations
- 8.3. Permutations with Repeats
- 8.4. Permutations with Indistinguishable Members
- 8.5. Calculating Combinations
- 8.6. Calculating Combinations II
- 8.7. Using Technology

### Chapter Summary

Students were introduced to the concepts of combinatorics. The differences between permutations and combinations were discussed. Students practiced the use of the formulas for calculating the number of possible combinations or permutations in various situations allowing or disallowing repeats and/or indistinguishable members.