Пошаговое объяснение:

№4

1) 8 23/25 - 3 7/10 = 8 46/50 - 3 35/50 = 5 11/50

2) 5 11/50 - 2 1/5 = 5 11/50 - 2 10/50 = 3 1/50

№5

1) 4 1/6 + 11 3/4 = 4 4/24 + 11 18/24 = 15 22/24 = 15 11/12

2) 19 - 15 11/12 = 18 12/12 - 15 11/12 = 3 1/12

№6

1) 7 - 2 7/10 = 6 10/10 - 2 7/10 = 4 3/10

2) 2 5/6 + 4 3/10 = 2 25/30 + 4 9/30 = 6 34/30 = 7 4/30 = 7 2/15