Ответ:

  1. 4 4/33 + 3 7/33 = 7 11/33 = 7 1/3.
  2. 5 13/18 − 2 7/18 = 3 6/18 = 3 1/3.
  3. 23/48 − 13/48 + 5/48 = 15/48 = 5/16.
  4. 7/45 + 14/45 − 1/45 = 20/45 = 4/9.