Пошаговое объяснение:
1) 1/9 + 4/9 = 5/9
2) 7/8 - 3/8 = 4/8 = 1/2
3) 15/19 - 6/19 = 9/19
4) 5/16 + 1/16 = 6/16 = 3/8
5) 3/14 + 11/14 = 14/14 = 1
6) 11/21 + 4/21 = 15/21 = 5/7
