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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 736 · 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 196 + 774? (a) 800 (b) 1200 (c) 1000
  2. 2.Best estimate of 44 × 39? (a) 1600 (b) 160 (c) 16000
  3. 3.Best estimate of 19 × 19? (a) 400 (b) 4000 (c) 40
  4. 4.Best estimate of 834 + 360? (a) 1200 (b) 1000 (c) 1400
  5. 5.Best estimate of 274 + 637? (a) 900 (b) 700 (c) 1100
  6. 6.Best estimate of 540 + 391? (a) 700 (b) 1100 (c) 900
  7. 7.Best estimate of 675 + 142? (a) 800 (b) 1000 (c) 600
  8. 8.Best estimate of 53 × 71? (a) 3500 (b) 350 (c) 35000
  9. 9.Best estimate of 34 × 69? (a) 210 (b) 21000 (c) 2100
  10. 10.Best estimate of 34 × 32? (a) 900 (b) 9000 (c) 90
  11. 11.Best estimate of 69 × 81? (a) 5600 (b) 560 (c) 56000
  12. 12.Best estimate of 418 + 398? (a) 600 (b) 1000 (c) 800
  13. 13.Best estimate of 93 × 87? (a) 81000 (b) 8100 (c) 810
  14. 14.Best estimate of 57 × 43? (a) 240 (b) 2400 (c) 24000
  15. 15.Best estimate of 60 × 47? (a) 30000 (b) 3000 (c) 300
  16. 16.Best estimate of 242 + 517? (a) 700 (b) 500 (c) 900
  17. 17.Best estimate of 83 × 83? (a) 640 (b) 64000 (c) 6400
  18. 18.Best estimate of 67 × 36? (a) 280 (b) 28000 (c) 2800
  19. 19.Best estimate of 21 × 94? (a) 18000 (b) 1800 (c) 180
  20. 20.Best estimate of 79 × 66? (a) 5600 (b) 56000 (c) 560
  21. 21.Best estimate of 721 + 457? (a) 1200 (b) 1400 (c) 1000
  22. 22.Best estimate of 42 × 84? (a) 32000 (b) 320 (c) 3200
  23. 23.Best estimate of 519 + 846? (a) 1500 (b) 1300 (c) 1100
  24. 24.Best estimate of 40 × 79? (a) 3200 (b) 32000 (c) 320
  25. 25.Best estimate of 36 × 56? (a) 24000 (b) 240 (c) 2400
  26. 26.Best estimate of 513 + 343? (a) 800 (b) 1000 (c) 600
  27. 27.Best estimate of 96 × 32? (a) 30000 (b) 3000 (c) 300
  28. 28.Best estimate of 26 × 20? (a) 600 (b) 60 (c) 6000
  29. 29.Best estimate of 97 × 72? (a) 70000 (b) 700 (c) 7000
  30. 30.Best estimate of 578 + 397? (a) 1200 (b) 1000 (c) 800
  31. 31.Best estimate of 773 + 574? (a) 1200 (b) 1600 (c) 1400
  32. 32.Best estimate of 50 × 32? (a) 1500 (b) 15000 (c) 150
  33. 33.Best estimate of 74 × 81? (a) 5600 (b) 56000 (c) 560
  34. 34.Best estimate of 36 × 28? (a) 1200 (b) 120 (c) 12000
  35. 35.Best estimate of 584 + 448? (a) 800 (b) 1000 (c) 1200
  36. 36.Best estimate of 19 × 58? (a) 120 (b) 12000 (c) 1200
  37. 37.Best estimate of 46 × 59? (a) 30000 (b) 3000 (c) 300
  38. 38.Best estimate of 74 × 70? (a) 49000 (b) 4900 (c) 490
  39. 39.Best estimate of 28 × 67? (a) 21000 (b) 2100 (c) 210
  40. 40.Best estimate of 149 + 651? (a) 800 (b) 1000 (c) 600

Answer key

  1. 1000
  2. 1600
  3. 400
  4. 1200
  5. 900
  6. 900
  7. 800
  8. 3500
  9. 2100
  10. 900
  11. 5600
  12. 800
  13. 8100
  14. 2400
  15. 3000
  16. 700
  17. 6400
  18. 2800
  19. 1800
  20. 5600
  21. 1200
  22. 3200
  23. 1300
  24. 3200
  25. 2400
  26. 800
  27. 3000
  28. 600
  29. 7000
  30. 1000
  31. 1400
  32. 1500
  33. 5600
  34. 1200
  35. 1000
  36. 1200
  37. 3000
  38. 4900
  39. 2100
  40. 800

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