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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 670 · 40 questions
TalentJR

How to do it in your head (Round, then work): Round each number: 2-digit numbers to the nearest ten, 3-digit numbers to the nearest hundred. Do the easy sum with the round numbers. Choose the option closest to your estimate.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 717 + 224? (a) 900 (b) 1100 (c) 700
  2. 2.Best estimate of 87 × 63? (a) 5400 (b) 540 (c) 54000
  3. 3.Best estimate of 175 + 392? (a) 600 (b) 800 (c) 400
  4. 4.Best estimate of 37 × 98? (a) 4000 (b) 400 (c) 40000
  5. 5.Best estimate of 32 × 73? (a) 21000 (b) 210 (c) 2100
  6. 6.Best estimate of 868 + 612? (a) 1700 (b) 1300 (c) 1500
  7. 7.Best estimate of 87 × 16? (a) 18000 (b) 180 (c) 1800
  8. 8.Best estimate of 460 + 196? (a) 500 (b) 900 (c) 700
  9. 9.Best estimate of 332 + 511? (a) 600 (b) 800 (c) 1000
  10. 10.Best estimate of 96 × 53? (a) 50000 (b) 5000 (c) 500
  11. 11.Best estimate of 73 × 52? (a) 3500 (b) 35000 (c) 350
  12. 12.Best estimate of 628 + 265? (a) 900 (b) 700 (c) 1100
  13. 13.Best estimate of 755 + 526? (a) 1100 (b) 1300 (c) 1500
  14. 14.Best estimate of 39 × 54? (a) 20000 (b) 200 (c) 2000
  15. 15.Best estimate of 36 × 46? (a) 20000 (b) 2000 (c) 200
  16. 16.Best estimate of 21 × 41? (a) 8000 (b) 800 (c) 80
  17. 17.Best estimate of 593 + 513? (a) 1300 (b) 900 (c) 1100
  18. 18.Best estimate of 347 + 322? (a) 400 (b) 600 (c) 800
  19. 19.Best estimate of 235 + 825? (a) 800 (b) 1000 (c) 1200
  20. 20.Best estimate of 606 + 499? (a) 1100 (b) 1300 (c) 900
  21. 21.Best estimate of 84 × 42? (a) 320 (b) 3200 (c) 32000
  22. 22.Best estimate of 39 × 64? (a) 240 (b) 2400 (c) 24000
  23. 23.Best estimate of 32 × 56? (a) 1800 (b) 180 (c) 18000
  24. 24.Best estimate of 52 × 19? (a) 1000 (b) 100 (c) 10000
  25. 25.Best estimate of 76 × 44? (a) 320 (b) 3200 (c) 32000
  26. 26.Best estimate of 219 + 695? (a) 700 (b) 1100 (c) 900
  27. 27.Best estimate of 244 + 597? (a) 600 (b) 800 (c) 1000
  28. 28.Best estimate of 488 + 429? (a) 900 (b) 700 (c) 1100
  29. 29.Best estimate of 548 + 134? (a) 600 (b) 400 (c) 800
  30. 30.Best estimate of 24 × 57? (a) 12000 (b) 120 (c) 1200
  31. 31.Best estimate of 871 + 424? (a) 1500 (b) 1300 (c) 1100
  32. 32.Best estimate of 515 + 531? (a) 800 (b) 1200 (c) 1000
  33. 33.Best estimate of 589 + 261? (a) 900 (b) 700 (c) 1100
  34. 34.Best estimate of 56 × 72? (a) 42000 (b) 420 (c) 4200
  35. 35.Best estimate of 12 × 67? (a) 700 (b) 7000 (c) 70
  36. 36.Best estimate of 48 × 82? (a) 40000 (b) 4000 (c) 400
  37. 37.Best estimate of 39 × 40? (a) 160 (b) 16000 (c) 1600
  38. 38.Best estimate of 23 × 92? (a) 1800 (b) 18000 (c) 180
  39. 39.Best estimate of 37 × 40? (a) 1600 (b) 160 (c) 16000
  40. 40.Best estimate of 46 × 84? (a) 400 (b) 4000 (c) 40000

Answer key

  1. 900
  2. 5400
  3. 600
  4. 4000
  5. 2100
  6. 1500
  7. 1800
  8. 700
  9. 800
  10. 5000
  11. 3500
  12. 900
  13. 1300
  14. 2000
  15. 2000
  16. 800
  17. 1100
  18. 600
  19. 1000
  20. 1100
  21. 3200
  22. 2400
  23. 1800
  24. 1000
  25. 3200
  26. 900
  27. 800
  28. 900
  29. 600
  30. 1200
  31. 1300
  32. 1000
  33. 900
  34. 4200
  35. 700
  36. 4000
  37. 1600
  38. 1800
  39. 1600
  40. 4000

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