2/4
4/10 - 1/10
1/9 + 2/9
3/9
4/7 + 1/7
2/4 + 1/4
3/10
5/7
3/7
7/9
5/9
3/9 + 2/9
1 - 2/4
1/2 + 1/2
1
9/10 - 2/10
3/4
7/10
5/7 - 2/7
8/9 - 1/9