Пошаговое объяснение:

3 5/9 + 4 2/3 = 3 5/9 + 4 6/9 = 10 2/9

7 -2 5/7 = 5 5/7

11 7/15 - 6 2/3= 11 7/15 - 6 10/15 = 4 5/15

13/18 * 5 1/7 = 13/18 * 36/7 = 13 * 36/18*7 = 468/126 = 3 90/126