【答案】1/6+1/12+1/20+1/30+1/42的简便过程

问题描述：

详细过程，数别变，比如把1/6变成1/2，不行不行

解法一：

1/6+1/12+1/20+1/30+1/42

=1/(2x3)+1/(3x4)+1/(4x5)+1/(5x6)+1/(6x7)

=(1/2-1/3)+(1/3-1/4)+……+(1/6-1/7)

=1/2-1/7

=5/14

解法二：

1/6+1/12+1/20+1/30+1/42

=(1/6+1/12)+(1/20+1/30)+1/42

=1/4+1/12+1/42

=1/3+1/42

=5/14