Ответ:

остальне здалаю через пару минут

Пошаговое объяснение:

5/16 + 11/12 = 15/48 + 33/48 = 48/48 = 1

5/21 + 5/28 = 20/84 + 15/84 = 35/84 = 5/12

15/19 + 27/38 = 30/38 + 27/38 = 57/38 = 3/2 = 1 1/2

9/20 - 5/12 = 27/60 - 25/60 = 2/60 = 1/30

7/18 - 1/45 = 35/90 - 2/90 = 33/90 = 11/30

11/42 - 5/28 = 22/84 - 15/84 = 7/84 = 1/12