1) 5/14 (3/5 + 13/25)
= 5/14 (15/25 + 13/25)
= 5/14 * 28/25
= 140/350
= 2/5

2) 1 1/2 (4 11/28 - 2 1/2)
= 3/2 (119/28 - 5/2)
= 3/2 (119/28 - 70/28)
= 3/2 49/28
= 147/56
= 2 19/56

3) 5 1/3 3 3/8 - 1 3/8
= 16/3 27/8 - 11/8
= 432/24 - 11/8
= 216/12 - 33/24
= 183/12
= 15 3/12
= 15 1/4

4) 1 3/4 1 11/21 - 11/21
= 7/4 32/21 - 11/21
= 224/84 - 11/21
= 224/84 - 44/84
= 180/84
= 45/21
= 2 1/7

Итак, результаты вычислений:
1) 2/5
2) 2 19/56
3) 15 1/4
4) 2 1/7