Arithmetic Grade Five

Lesson Seventy-eight: Computing Averages

Sometimes when calculating averages we want our answer to be rounded off to the nearest whole number. 

    FIND THE AVERAGE OF: 6, 7, 11, 7, 5, 4.

    STEP ONE: 6 + 7 + 11 + 7 + 5 + 4 = 40.

    STEP TWO: 40 / 6 = 6 r4.

    STEP THREE: ROUND TO NEAREST WHOLE -

                 Write the remainder as a fraction over the divisor:

                   4/6

                 If the fraction is 1/2 or greater round the answer up,
                 otherwise leave it alone.

    ANSWER: 7
Here's another example: 

     Compute the average: 21, 24, 22, 23, 22, 20, 26, 25.

     STEP ONE: 21 + 24 + 22 + 23 + 22 + 20 + 26 + 25 = 183

     STEP TWO: 183 / 8 = 22 r7

     STEP THREE: ROUND TO NEAREST WHOLE -

                  Write the remainder as a fraction over the divisor:

                     7/8

                  If the fraction is 1/2 or greater round the answer up,
                  otherwise leave it alone.

     ANSWER: 23
You get to try a few for yourself on the next page.

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