Ответ:

  1. 18 + 18 = 36.
  2. 16 + 16 = 32.
  3. 35 + 37 = 72.
  4. 45 + 46 = 91.
  5. 57 + 27 = 84.
  6. 39 + 59 = 98.
  7. 12 + 19 + 9 = 12 + (19 + 9) = 12 + 28 = 40.
  8. 17 + 18 + 5 = 17 + (18 + 5) = 17 + 23 = 40.