l1/3-1/2l+l1/4-1/3l+l1/5-1/4l+...+l1/100-1/99l.
问题描述：
l1/3-1/2l+l1/4-1/3l+l1/5-1/4l+...+l1/100-1/99l.
答
原式=1/2-1/3+1/3-1/4+.+1/99-1/100
=1/2-1/100
=49/100