1) 5/13: 3 + 2/39 * 2-5 / 39 + 4/3939 / 39-1 / 13
2) 7/33 * 5 + 2/11: 3-35 / 33 + 2 / 33-37 / 33-1 4/33
3) (20/23 + 26/23): 2-46 / 23: 2-46 / 46-1
4) (67 / 10-17 / 10): 5-50 / 10: 5-50 / 50-1
