问题描述: 7/6+13/12+21/20+30/31+42/43+57/56+73/72+91/90=? 1个回答 分类:数学 2014-11-23 问题解答: 我来补答 7/6+13/12+21/20+31/30+43/42+57/56+73/72+91/90=1+1/6+1+1/12+1+1/20+1/30+1+1/42+1+1/56+1+1/72+1+1/90=8+(1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90)=8+(1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10)=8+2/5=8又2/5 展开全文阅读