一道数学计算题很难!求 12*1/13+13*1/14+14*1/15+...+20*1/21(一定要过程!!!!!!!!!!!!!!!!!!!!!!!!!!!!!)
2019-04-13
一道数学计算题
很难!
求 12*1/13+13*1/14+14*1/15+...+20*1/21
(一定要过程!!!!!!!!!!!!!!!!!!!!!!!!!!!!!)
优质解答
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