Sections:

# Counting Theory

About:

Additional Resources:

In this lesson, we will learn about combinations and permutations. These problems involve the number of ways of selecting r items out of n items, where repetitions are not allowed. If the order is important, meaning changing the order changes the result, we want to use the formula for permutations. If the order is not important, meaning changing the order does not change the result, we want to use the formula for combinations.

Counting Theory:

Videos:

Better Explained - Video Khan Academy - Video Text Lessons:

Math is Fun - Text Lesson Better Explained - Text Lesson + Show More +