Question

If the water level at the lake continued to change at the same rate for 3 months in a row explain how you could estimate the total change in the water level at the end of the 3 months period.

Answer 1

Multiply the 1-month change by 3 to get the 3-month change.

Explanation:

You could add up the changes for the three months. Your problem statement tells you to assume they are the same:

3-month change = (1-month change) + (1-month change) + (1-month change)

3-month change = 3×(1-month change)

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Multiplication was invented to simplify repeated addition.