1. 1/7 + 5/7 =
2. 5/14 + 3/14 =
3. 8 9/20 + 7 2/20 =
4. 1/5 + 2/7 =
5. 1/4 + 3/5 =
6. 2/3 - 4/15 =
7. 4/7 - 1/7 =
8. 1 2/5 - 1/2 =
9. 2/4 - 1/3 =
10. 3 1/2 - 2 5/8 =
​