AMC 8 1989 Problem 4
AMC8 1989 年第 4 题
表达式与运算★☆☆☆☆
Estimate to determine which of the following numbers is closest to .
估算 最接近以下哪个数。
- A.0.2
- B.2
- C.20
- D.200
- E.2000
正确答案 · Correct Answer
E
解析 · Solution
Solution 1
By rounding,
Using scientific notation estimated to the first significant digit, we see the numerator rounds to . Subtracting the exponents gives 2-(-1)=3. The answer choice that has 3 zeros to the right of the significant digit is
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