一减六分之五加十二分之七减二十分之九加三十分之十一减四十二分之十三加五十六分之十五减七十二分之十七加九十分之十九
一减六分之五加十二分之七减二十分之九加三十分之十一减四十二分之十三加五十六分之十五减七十二分之十七加九十分之十九
=1-5/6+7/12-9/20+11/30-13/42+15/56-17/72+19/90
=1-1/2-1/3+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
=1/2+1/10
=6/10
=5分之3
=1-5/6+7/12-9/20+11/30-13/42+15/56-17/72+19/90
=1-1/2-1/3+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
=1/2+1/10
=6/10
=5分之3
温馨提示:答案为网友推荐,仅供参考
第1个回答 2012-12-19
解:1-5/6+7/12-9/20+11/30-13/42+15/56-17/72+19/90
=1-(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)
=1-1/2-1/3+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
=1-1/2+1/10
=1/2+1/10
=6/10
=3/5
=1-(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)
=1-1/2-1/3+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
=1-1/2+1/10
=1/2+1/10
=6/10
=3/5
第2个回答 2012-12-19
5/6=1/3+1/2 同理7/12=1/3+1/4 ,类推 结果为3/5.
第3个回答 2012-12-19
计算器!!!!!