Averages at a Glance

Averages often appear on word problems. To find the average of a collection of numbers, we add all the numbers and then divide by how many numbers there are. If someone calls you average and they haven't done all the legwork, you can disregard their judgment of you.

Sample Problem

Find the average of the five smallest positive integers.

The five smallest positive integers are 1, 2, 3, 4, and 5. Remember, integers are counting numbers, and if you're counting down to a shuttle launch, you'll rarely use fractions. Unless there's some sort of mechanical malfunction and you're stalling for time. "Two...uh, one and a half..." 

To find the average of these, we add them and divide by 5, since that's how many numbers we have.

Example 1

The average of 5 and what number is 9?