Arithmetic Grade Four

Lesson Seventy-nine: Computing Averages

Finding Averages of Three Numbers - To find the average of three numbers you first find their sum and then you divide this sum by three. You did some problems like this before, but these answers will have remainders. 

     Compute the average: 31, 30, 28.

     STEP ONE: 31 + 30 + 28 = 89

     STEP TWO: 89 / 3 = 29 2/3
Here's another example: 

     Compute the average: 21, 24, 22.

     STEP ONE: 21 + 24 + 22 = 67

     STEP TWO: 67 / 3 = 22 1/3
Here's one more example: 

     Compute the average: 11, 9, 8.

     STEP ONE: 11 + 9 + 8 = 28

     STEP TWO: 28 / 3 = 9 1/3
You get to try a few for yourself on the next page.

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