计算:1-3/2+5/6-7/12+……-19/20+21/110
问题描述:
计算:1-3/2+5/6-7/12+……-19/20+21/110
答
(1-3/2)+(5/6-7/12)+(9/20-11/30)+(13/42-15/56)+(17/72-19/90)+21/110
=(-1/2+1/4+1/12+1/24+1/40)+21/110
=-1/10+21/110
=-1/11