Ответ:

  1. 48 + 32 = 48 + 2 + 30 = 50 + 30 = 80.
  2. 51 + 19 = 51 + 9 + 10 = 60 + 10 = 70.
  3. 64 + 26 = 64 + 6 + 20 = 70 + 20 = 90.
  4. 15 + 35 = 15 + 5 + 30 = 20 + 30 = 50.