Ответ:

  1. \(12+38-33=50-33=17\).
  2. \(55-(20+8)=55-28=27\).
  3. \(42-16-20=26-20=6\).
  4. \(8\cdot3:6=24:6=4\).
  5. \(3\cdot(8:2)=3\cdot4=12\).
  6. \(36:9\cdot7=4\cdot7=28\).
  7. \((48-16):8=32:8=4\).
  8. \(14+35:7=14+5=19\).
  9. \(6\cdot(20-16)=6\cdot4=24\).
  10. \(3\cdot4:6=12:6=2\).
  11. \(9\cdot2:3=18:3=6\).
  12. \(6\cdot4:8=24:8=3\).