1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72

来源：学生作业帮助网编辑：六六作业网时间：2024/05/06 16:02:41

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/721/2+1/6+1/12+1/20+1/30+1/42+1/56+1/721/2+1/6+1/12+1/20+1/30+1/4

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
=(1-1/2)+(1/2-1/3)+……+(1/7-1/8)+(1/8-1/9) (中间相互抵消）
=1-1/9
=8/9
不懂问我.