Ответ:

  1. 10 − (3 + 4) = 10 − 7 = 3.
  2. 7 + (8 − 2) = 7 + 6 = 13.
  3. 15 − (9 − 3) = 15 − 6 = 9.
  4. 12 + (10 − 8) = 12 + 2 = 14.
  5. 11 − (5 + 5) = 11 − 10 = 1.
  6. 8 + (17 − 10) = 8 + 7 = 15.
  7. 20 − (6 + 4) = 20 − 10 = 10.
  8. 9 + (4 + 5) = 9 + 9 = 18.
  9. 10 + (13 − 3) = 10 + 10 = 20.
  10. 2 + (9 + 9) = 2 + 18 = 20.
  11. 14 − (12 − 8) = 14 − 4 = 10.
  12. 13 − (3 + 5) = 13 − 8 = 5.