1/3+1/6+1/10+1/15+1/21+1/21+1/28=?要简单. 详细.要快。

来源：学生作业帮助网编辑：作业帮时间：2024/05/15 05:37:20

1/3+1/6+1/10+1/15+1/21+1/21+1/28=?要简单. 详细.要快。
1/3+1/6+1/10+1/15+1/21+1/21+1/28=?
要简单.
详细.
要快。

1/3+1/6+1/10+1/15+1/21+1/21+1/28=?要简单. 详细.要快。
1/3+1/6+1/10+1/15+1/21+1/21+1/28
=1/3+(1/2-1/3)+(1/6-1/15)+1/15+(1/12-1/28)+1/21+1/28
=1/2+1/6+1/12+1/21
=3/4+1/21
=67/84

=1/2+1/6+2/21+1/28
=2/3+2/21+1/28
=16/21+1/28
=67/84

=1/3+(1/2-1/3)+(1/6-1/15)+1/15+(1/12-1/28)+1/21+1/28
=1/2+1/6+1/12+1/21
=3/4+1/21
=67/84