A distance runner is running an 18-mile race. So far, she has run 43% of the race.Which would be the best way to estimate the number of miles the runner has run so far?

To estimate 43% of 18 miles, round 43% to 40% and 18 miles to 20 miles. Then find 40% of 20, which is 8 miles. This is close to the exact amount, 43% of 18 = 7.74 miles, so the best method is “Find 40% of 20.”

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