Ответ:

  1. 125 × ((48 + 8) − 8) = 125 × 48 = 6000.
  2. (39 + 61 + 1) × 25 = 101 × 25 = 2525.
  3. 125 × (72 ÷ 9) = 125 × 8 = 1000.
  4. 3000 ÷ 30 = 100.
  5. 840 × 100 ÷ 4 = 84 000 ÷ 4 = 21 000.
  6. 90 + 80 = 170.
  7. 64 × 100 = 6400.
  8. (48 + 52 − 20) × 35 = 80 × 35 = 2800.
  9. 2400 ÷ 8 ÷ 5 = 300 ÷ 5 = 60.
  10. 250 × ((16 + 24) − 20) = 250 × 20 = 5000.
  11. (999 + 1) × 48 = 1000 × 48 = 48 000.
  12. 1000 × 8 = 8000.
  13. 54 ÷ 9 × 125 + 250 = 6 × 125 + 250 = 750 + 250 = 1000.
  14. 1200 ÷ 10 + 1200 ÷ 15 = 120 + 80 = 200.
  15. 1200 ÷ 12 + 200 = 100 + 200 = 300.