Verified answer

Пошаговое объяснение:

№1

1) 1/5 * 3/4 = 3/20

2) 3/20 * 2/3 = 1/10 * 1/1 = 1/10

№2

1) 3/10 * 7/8 = 21/80

2) 2/9 * 21/80 = 1/3 * 7/40 = 7/120

№3

1) 19/25 * 7/9 = 133/225

2) 15/19 * 133/225 = 1/1 * 7/15 = 7/15

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

№4

1) 10/13 * 11/12 = 5/13 * 11/6 = 55/78

2) 12/55 * 13/20 = 3/55 * 13/5 = 39/275

3) 55/78 * 39/275 = 1/2 * 1/5 = 1/10