Problem 3 · 2015 Math Kangaroo
Easy
Fractions, Decimals & Percents
estimate-and-pick
Which of the following numbers is closest to the product \(2.015 \times 510.2\)?
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Answer: E — 1000
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Hint 1 of 2
Round each factor to an easy nearby number before multiplying.
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Hint 2 of 2
\(2.015\) is about 2 and \(510.2\) is about 510, so estimate \(2 \times 510\).
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Approach: estimate by rounding the factors
- Replace \(2.015\) by 2 and \(510.2\) by 510.
- \(2 \times 510 = 1020\).
- Among the choices, 1020 is closest to 1000.
- So the answer is 1000 (E).
Mark:
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