魔法苹果99
幼苗
共回答了16个问题采纳率:87.5% 举报
1.1/2+1/6+1/12+1/20+1/30+1/42
=(1--1/2)+(1/2--1/3)+(1/3--1/4)+(1/4--1/5)+(1/5--1/6)+(1/6--1/7)
=1--1/7
=6/7.
2.8又3分之2加4分之7乘以7分之5
=8+2/3+5/4
=8+(8/12+15/12)
=8+23/12
=9又12分之11.
3.9又2分之1除以3
=(9+1/2)X1/3
=3+1/6
=3又6分之1.
1年前
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