To subtract 3/15 from 2 7/25:

2 7/25 = 50/25 + 7/25 = 57/25

To subtract 3/15 from 57/25, we need to find a common denominator:

15 = 3 5
25 = 5 5

So, the common denominator is 15 * 5 = 75

57/25 = 57 3/75 = 171/75
3/15 = 3 5/75 = 15/75

Therefore, 57/25 - 3/15 = 171/75 - 15/75 = 156/75 = 2 6/25

To add 1 2/25 and 1 4/13:

1 2/25 = 50/25 + 2/25 = 52/25
1 4/13 = 13/13 + 4/13 = 17/13

To add 52/25 and 17/13, we need to find a common denominator:

25 = 5 5
13 = 13 1

So, the common denominator is 25 * 13 = 325

52/25 = 52 13/325 = 676/325
17/13 = 17 25/325 = 425/325

Therefore, 52/25 + 17/13 = 676/325 + 425/325 = 1101/325 = 3 426/325