Ответ:

Пошаговое объяснение:

1) 1/2 : 1/3 = 1/2 * 3/1 = 3/2 = 1. 1/2

2) 1. 2/3 : 2. 1/5 = 5/3 : 11/5 = 5/3 * 5/11 = 25/33

3.

1) 1. 2/3 + 2. 5/9 = 1. 6/9 +

2. 5/9 = 3. 11/9 = 4. 2/9

2) 4. 42/45 - 2. 3/5 = 4. 42/45 - 2. 27/45 = 2. 15/45 = 2. 1/3

3) 4. 2/9 : 2. 1/3 = 38/9 : 7/3 = 38/9 * 3/7 = 38/3 * 1/7 = 38/21 = 1. 17/21

4.

4. 1/5 * 3/7 = 21/5 * 3/7 =

3/5 * 3/1 = 9/5 = 1. 4/5