问三道数学题,请尽快回答!用简便方法计算:(1)1/2+1/3+1/4+1/5+1/6=?(2)(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5+1/6)+(1/6-1/7)+(1/7-1/8)=?(3)1/2+1/3+1/4+1/5+1-1/5-1/4-1/3-1/2=?
问题描述:
问三道数学题,请尽快回答!
用简便方法计算:
(1)1/2+1/3+1/4+1/5+1/6=?
(2)(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5+1/6)+(1/6-1/7)+(1/7-1/8)=?
(3)1/2+1/3+1/4+1/5+1-1/5-1/4-1/3-1/2=?
答
(1)29/20
(2)1/2-1/8=3/8
(3)1