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629-320 14个连续整数问求和是否大于0
1.有七个正数
2.有-7这个数
选A
对,A
1)因为最小的和是从-6+-5。。。+-1+0 + 1+。。+ 7总共14个,结果是=7,所以肯定大于0
2)不行,只有一个更不能确定
I think is D, because if -7 is in the set, so the largest sum is from -7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6. So it must be less than 0. and if -7 isn't the smallest number of the set, the sum defenit less than 0 too.
Sorry I can't type Chinese with the campus PC. |
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