帮忙解六年级奥数题。高分悬赏。。（一共4题）

什么乱七八糟的啊。。。。。我有杀死你的念头，好不容易做出来了，一看后面竟然还有个“分之一”

=214

1..
(1/2+1/3+1/4)x(1/3+1/4+1/5)-(1/2+1/3+1/4+1/5)x(1/3+1/4)
= (1/2+1/3+1/4)x(1/3+1/4+1/5)-[(1/2+1/3+1/4)+1/5]x[(1/3+1/4+1/5)-1/5]
= (1/2+1/3+1/4)x(1/3+1/4+1/5)-(1/2+1/3+1/4)x(1/3+1/4+1/5) - 1/5 * (1/3+1/4+1/5) +
1/5 (1/2+1/3+1/4)+ 1/5 *1/5
= 1/5 (1/2-1/5+1/5)
= 1/10

2.
= 1/5 * (1/2 - 1/7) + 1/5 (1/7-1/12) + 1/5 (1/12 - 1/17)
= 1/5[1/2 - 1/7 + 1/7-1/12 + 1/12 - 1/17]
= 1/5 * (1/2 - 1/17)
= 3 / 34

3. 貌似不对，似乎是三十分之十一？
4题没有读懂。。。。。

1.(1/2+1/3+1/4)x(1/3+1/4+1/5)-(1/2+1/3+1/4+1/5)x(1/3+1/4)
=(1/2+1/3+1/4)x(1/3+1/4+1/5)-(1/2+1/3+1/4)x(1/3+1/4)-(1/3+1/4+1/5)
=(1/2+1/3+1/4)x(1/3+1/4+1/5-1/3-1/4)-(1/3+1/4+1/5)
=(1/2+1/3+1/4+1/5)-(1/3+1/4+1/5)
=1/2
2.