1/2X1/3-1/3X1/4-1/4X1/5-1/5X1/6.-1/39X1/40

来源：学生作业帮助网编辑：六六作业网时间：2024/11/27 02:29:23

1/2X1/3-1/3X1/4-1/4X1/5-1/5X1/6.-1/39X1/401/2X1/3-1/3X1/4-1/4X1/5-1/5X1/6.-1/39X1/401/2X1/3-1/3X1/4-

1/2X1/3-1/3X1/4-1/4X1/5-1/5X1/6.-1/39X1/40
1/2X1/3-1/3X1/4-1/4X1/5-1/5X1/6.-1/39X1/40

1/2X1/3-1/3X1/4-1/4X1/5-1/5X1/6.-1/39X1/40
1/2X1/3=1/2--1/3
1/3X1/4=1/3--1/4
.
依次类推最后结果=1/2--1/140=69/140

1111