-1/2+5/6-7/12+9/20-11/30+13/42-15/56+17/72=?
问题描述:
-1/2+5/6-7/12+9/20-11/30+13/42-15/56+17/72=?
-1/2=负二分之一
......
答
-1/2+5/6-7/12+9/20-11/30+13/42-15/56+17/72
=-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