帮我出30题分数加减的题目.15题加,15题减.

1/2+2/3
2/3+3/4
3/4+4/5
4/5+5/6
5/6+6/7
6/7+7/8
7/8+8/9
8/9+9/10
9/10+10/11
10/11+11/12
11/12+12/13
12/13+13/14
13/14+14/15
14/15+15/16
15/16+16/17
1/2-2/3
2/3-3/4
3/4-4/5
4/5-5/6
5/6-6/7
6/7-7/8
7/8-8/9
8/9-9/10
9/10-10/11
10/11-11/12
11/12-12/13
12/13-13/14
13/14-14/15
14/15-15/16
15/16-16/17