来吸口烟吧
幼苗
共回答了20个问题采纳率:85% 举报
1+1/2-2-5/6+3+1/12-4-19/20+5+1/30-6-41/42+7+1/56-8-71/72+9+1/90
=1+1/2-3+1/6+3+1/12-5+1/20+5+1/30-7+1/42+7+1/56-9+1/72+9+1/90
=1+(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)+(1/7-1/8)+(1/8-1/9)+(1/9-1/10)
=1+1-1/10
=19/10
1年前
1