Ответ:

  1. \(450 : 3 = 150\)
  2. \(190 \cdot 3 = 570\)
  3. \(180 \cdot 5 = 900\)
  4. \(230 \cdot 4 = 920\)
  5. \(300 \cdot 3 = 900\)
  6. \(750 : 3 = 250\)
  7. \(140 \cdot 3 = 420\)
  8. \(110 \cdot 7 = 770\)
  9. \(840 : 4 = 210\)
  10. \(492 : 4 = 123\)
  11. \(416 : 8 = 52\)
  12. \(560 : 4 = 140\)
  13. \(220 \cdot 4 = 880\)
  14. \(320 \cdot 3 = 960\)
  15. \(950 : 5 = 190\)
  16. \(880 : 4 = 220\)
  17. \(287 : 7 = 41\)
  18. \(726 : 6 = 121\)
  19. \(130 \cdot 6 = 780\)
  20. \(290 \cdot 3 = 870\)
  21. \(110 \cdot 8 = 880\)

Ответ: 150; 570; 900; 920; 900; 250; 420; 770; 210; 123; 52; 140; 880; 960; 190; 220; 41; 121; 780; 870; 880.