- 3/8 + (- 1/2) = - 3/8 - 1/2 =- 3/8 - 4/8 = - 7/8
3/7 + 1 + (- 3/7) = 3/7 - 3/7 + 1 = 1
5/12 - (- 1/12) = 5/12 + 1/12 = 6/12 = 1/2
- 4/9 - 2/3 = - 4/9 - 6/9 = - 10/9 = - 1ц 1/9
- 7/15 - (- 2/15) = - 7/15 + 2/15 = - 5/15 = - 1/3
- 2/15 - (- 7/15) = - 2/15 + 7/15 = 5/15 = 1/3
- 5/12 - (- 7/12) = - 5/12 + 7/12 = 2/12 = 1/6
5/7 - 13/14 = 10/14 - 13/14 = - 3/14
- 5/9 - (- 2/3) = - 5/9 + 2/3 = - 5/9 + 6/9 = 1/9
- 1/2 - (- 1/4) = -1/2 + 1/4 = - 2/4 + 1/4 = - 1/4