Estimate 9.8 ÷ 0.49 by using the nearby benchmarks 10 and 0.5.

الشرح

Using the stated benchmarks gives 10 ÷ 0.5 = 20, and the exact calculation 9.8 ÷ 0.49 also equals 20. An estimate of 5 comes from multiplying the benchmarks, which is the wrong operation.