简便计算:一又三分之-7/12+9/20-11/30=13/42-15/56

问题描述:

简便计算:一又三分之-7/12+9/20-11/30=13/42-15/56

一又三分之-7/12+9/20-11/30+13/42-15/56
=(1+1/3)-(1/3+1/4)+(1/4+1/5)-(1/5+1/6)+(1/6+1/7)-(1/7+1/8)
=1-1/8
=7/8