AMC 8 2014 Problem 1
AMC8 2014 年第 1 题
表达式与运算★☆☆☆☆
Harry and Terry are each told to calculate 8-(2+5) . Harry gets the correct answer. Terry ignores the parentheses and calculates 8-2+5 . If Harry's answer is and Terry's answer is , what is H-T ?
Harry 和 Terry 都被要求计算 $8-(2+5)$。Harry 算对了，而 Terry 忽略了括号，计算的是 8-2+5。若 Harry 的答案是 ，Terry 的答案是 ，那么 H-T 是多少？
- A.-10
- B.-6
- C.0
- D.6
- E.10
正确答案 · Correct Answer
A
解析 · Solution
Solution 1
We have H=8-7=1 and T=8-2+5=11. Clearly 1-11=-10, so our answer is -10.
We use PEMDAS, 8-(2+5) is the same as 8-7 which is 1, 8-2+5 is the same as 6+5 because 8-2 comes first, and the sum is 11. H-T is 1-11 which is -10.
Harry, who calculates it correctly, gets 8 - 7 = 1. Terry, who calculates it without parenthesis gets 8 - 2 + 5 which is 6 + 5 = 11. 1 - 11 = -10 -JasonDaGoat
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