=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1/2-1/6
=1/36分之5加12分之7加20分之9 计算 要过程=(1/3+1/2)+(1/4+1/3)+(1/5+1/4)=1/2+1/5+2*(1/3+1/4)=7/10+7/6=21/30+35/30=56/30=28/15