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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 907 · 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 39 × 38? (a) 160 (b) 1600 (c) 16000
  2. 2.Best estimate of 296 + 404? (a) 500 (b) 700 (c) 900
  3. 3.Best estimate of 37 × 43? (a) 1600 (b) 16000 (c) 160
  4. 4.Best estimate of 96 × 89? (a) 9000 (b) 900 (c) 90000
  5. 5.Best estimate of 89 × 76? (a) 72000 (b) 720 (c) 7200
  6. 6.Best estimate of 16 × 44? (a) 80 (b) 8000 (c) 800
  7. 7.Best estimate of 21 × 56? (a) 12000 (b) 120 (c) 1200
  8. 8.Best estimate of 37 × 92? (a) 3600 (b) 36000 (c) 360
  9. 9.Best estimate of 174 + 507? (a) 700 (b) 900 (c) 500
  10. 10.Best estimate of 16 × 67? (a) 1400 (b) 14000 (c) 140
  11. 11.Best estimate of 63 × 63? (a) 36000 (b) 360 (c) 3600
  12. 12.Best estimate of 53 × 66? (a) 35000 (b) 3500 (c) 350
  13. 13.Best estimate of 602 + 665? (a) 1300 (b) 1100 (c) 1500
  14. 14.Best estimate of 41 × 46? (a) 200 (b) 2000 (c) 20000
  15. 15.Best estimate of 58 × 67? (a) 4200 (b) 42000 (c) 420
  16. 16.Best estimate of 46 × 82? (a) 400 (b) 40000 (c) 4000
  17. 17.Best estimate of 28 × 43? (a) 1200 (b) 12000 (c) 120
  18. 18.Best estimate of 510 + 508? (a) 1200 (b) 800 (c) 1000
  19. 19.Best estimate of 12 × 33? (a) 300 (b) 3000 (c) 30
  20. 20.Best estimate of 68 × 54? (a) 35000 (b) 3500 (c) 350
  21. 21.Best estimate of 207 + 544? (a) 900 (b) 500 (c) 700
  22. 22.Best estimate of 54 × 86? (a) 4500 (b) 45000 (c) 450
  23. 23.Best estimate of 96 × 47? (a) 50000 (b) 500 (c) 5000
  24. 24.Best estimate of 96 × 52? (a) 50000 (b) 500 (c) 5000
  25. 25.Best estimate of 14 × 66? (a) 700 (b) 7000 (c) 70
  26. 26.Best estimate of 96 × 79? (a) 80000 (b) 800 (c) 8000
  27. 27.Best estimate of 781 + 252? (a) 1100 (b) 900 (c) 1300
  28. 28.Best estimate of 215 + 864? (a) 1100 (b) 900 (c) 1300
  29. 29.Best estimate of 270 + 123? (a) 600 (b) 200 (c) 400
  30. 30.Best estimate of 68 × 20? (a) 1400 (b) 14000 (c) 140
  31. 31.Best estimate of 39 × 17? (a) 80 (b) 800 (c) 8000
  32. 32.Best estimate of 50 × 62? (a) 3000 (b) 300 (c) 30000
  33. 33.Best estimate of 47 × 78? (a) 40000 (b) 4000 (c) 400
  34. 34.Best estimate of 62 × 16? (a) 120 (b) 1200 (c) 12000
  35. 35.Best estimate of 27 × 36? (a) 1200 (b) 12000 (c) 120
  36. 36.Best estimate of 32 × 46? (a) 15000 (b) 150 (c) 1500
  37. 37.Best estimate of 79 × 16? (a) 1600 (b) 16000 (c) 160
  38. 38.Best estimate of 34 × 66? (a) 21000 (b) 2100 (c) 210
  39. 39.Best estimate of 46 × 66? (a) 35000 (b) 350 (c) 3500
  40. 40.Best estimate of 32 × 26? (a) 9000 (b) 90 (c) 900

Answer key

  1. 1600
  2. 700
  3. 1600
  4. 9000
  5. 7200
  6. 800
  7. 1200
  8. 3600
  9. 700
  10. 1400
  11. 3600
  12. 3500
  13. 1300
  14. 2000
  15. 4200
  16. 4000
  17. 1200
  18. 1000
  19. 300
  20. 3500
  21. 700
  22. 4500
  23. 5000
  24. 5000
  25. 700
  26. 8000
  27. 1100
  28. 1100
  29. 400
  30. 1400
  31. 800
  32. 3000
  33. 4000
  34. 1200
  35. 1200
  36. 1500
  37. 1600
  38. 2100
  39. 3500
  40. 900

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