Пошаговое объяснение:

№1

1) 4 1/5 : 7/15 = 21/5 * 15/7 = 3/1 * 3/1 = 9/1 = 9

2) 9 : 1/3 = 9 * 3/1 = 27/1 = 27

№2

1) 7/15 : 1/3 = 7/15 * 3/1 = 21/15 = 7/5

2) 4 1/5 : 7/5 = 21/5 * 5/7 = 3/1 * 1/1 = 3/1 = 3

№3

1) 2 1/4 + 4 5/6 = 2 3/12 + 4 10/12 = 6 13/12 = 7 1/12

2) 7 1/12 : 3 2/5 = 85/12 : 17/5 = 85/12 * 5/17 = 5/12 * 5/1 = 25/12 = 2 1/12

3) 3/4 : 3/5 = 3/4 * 5/3 = 1/4 * 5/1 = 5/4 = 1 1/4

4) 2 1/12 - 1 1/4 = 2 1/12 - 1 3/12 = 1 13/12 - 1 3/12 = 10/12 = 5/6

№4

1) 5 8/9 : 1 17/36 = 53/9 : 53/36 = 53/9 * 36/53 = 1/1 * 4/1 = 4/1 = 4

2) 4 + 1 1/4 = 5 1/4

3) 5 1/4 * 5/21 = 21/4 * 5/21 = 1/4 * 5/1 = 5/4 = 1 1/4