Ответ:

Пошаговое объяснение:

1)

1/4 + 2/7 = 7/28 + 8/28 = 15/28

2)

1/4 - 8/7 = 7/28 - 32/28 = -25/28

3)

2/9 + 4/7 = 14/63 + 36/63 = 50/63

4)

1 + 4/9 = 1. 4/9

5)

2. 1/3 + 8 = 10. 1/3

6)

1. 1/4 + 2. 1/8 =

1. 2/8 + 2. 1/8 = 3. 3/8

7)

4. 1/3 - 2/9 = 4. 3/9 - 2/9 = 4. 1/9

8)

6. 1/5 - 2/15 = 6. 3/15 - 2/15 = 6. 1/15

9)

7. 1/3 + 1/27 = 7. 9/27 + 1/27 = 7. 10/27

10)

4. 6/7 - 2. 7/8 =

4. 48/56 - 2. 49/56 =

3. 104/56 - 2. 49/56 =

1. 55/56