Пошаговое объяснение:

5 * 5 2/5 = 5 * 27/5 = 1 * 27/1 = 27/1 = 27

2 2/5 * 15/16 = 12/5 * 15/16 = 3/1 * 3/4 = 9/4 = 2 1/4

9 * 4 2/9 = 9 * 38/9 = 1 * 38/1 = 38/1 = 38

3 1/15 + 2 7/25 = 3 5/75 + 2 21/75 = 5 26/75

1 7/12 + 3 5/9 = 1 21/36 + 3 20/36 = 4 41/26 = 5 15/26

1 2/7 * 14/15 = 9/7 * 14/15 = 3/1 * 2/5 = 6/5 = 1 1/5