First use front-end rounding to write an estimate of the answer, and then multiply fully to obtain an exact answer.
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A)Estimate: 480, exact: 510.4136
B)Estimate: 48, exact: 51.04136
C)Estimate: 4.8, exact: 5.104136
D)Estimate: 480, exact: 5,104.136

Question

First use front-end rounding to write an estimate of the answer, and then multiply fully to obtain an exact answer.
-
A)Estimate: 480, exact: 510.4136 
B)Estimate: 48, exact: 51.04136 
C)Estimate: 4.8, exact: 5.104136 
D)Estimate: 480, exact: 5,104.136

Quizplus · Accepted Answer

To use front-end rounding, we look at the first digit after the decimal point: 4. Since it is less than 5, we round down the entire decimal to 0.04. Then we multiply fully: 0.04 x 127610 = 5104.136, which rounds to 51.04136. Therefore, the estimate is 48 and the exact answer is 51.04136. The other choices either round too high (A and D) or are too low (C).

First Use Front-End Rounding to Write an Estimate of the Answer