Joe Blue Was Estimating 92 × 31

Essay

Joe Blue was estimating 92 × 31. He said that rounding 31 to 30 then taking 92 × 30 (which is 2760) is a better estimate than rounding 92 to 90 and then taking 90 × 31 (which is 2790) because, in the first case, you lost only 1 by rounding 31 to 30, but, in the second case, you lost 2 by rounding 92 to 90. Explain how Joe's reasoning is INCORRECT. Your answer should show number sense.