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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 546 · 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 26 × 64? (a) 18000 (b) 1800 (c) 180
  2. 2.Best estimate of 63 × 74? (a) 420 (b) 4200 (c) 42000
  3. 3.Best estimate of 24 × 57? (a) 12000 (b) 120 (c) 1200
  4. 4.Best estimate of 554 + 287? (a) 1100 (b) 900 (c) 700
  5. 5.Best estimate of 78 × 76? (a) 64000 (b) 6400 (c) 640
  6. 6.Best estimate of 365 + 369? (a) 800 (b) 600 (c) 1000
  7. 7.Best estimate of 511 + 499? (a) 1200 (b) 1000 (c) 800
  8. 8.Best estimate of 12 × 56? (a) 600 (b) 6000 (c) 60
  9. 9.Best estimate of 746 + 675? (a) 1400 (b) 1600 (c) 1200
  10. 10.Best estimate of 62 × 36? (a) 24000 (b) 2400 (c) 240
  11. 11.Best estimate of 52 × 19? (a) 1000 (b) 10000 (c) 100
  12. 12.Best estimate of 76 × 90? (a) 720 (b) 7200 (c) 72000
  13. 13.Best estimate of 58 × 86? (a) 5400 (b) 540 (c) 54000
  14. 14.Best estimate of 67 × 57? (a) 42000 (b) 420 (c) 4200
  15. 15.Best estimate of 577 + 179? (a) 800 (b) 600 (c) 1000
  16. 16.Best estimate of 83 × 38? (a) 3200 (b) 32000 (c) 320
  17. 17.Best estimate of 29 × 58? (a) 18000 (b) 180 (c) 1800
  18. 18.Best estimate of 264 + 409? (a) 900 (b) 500 (c) 700
  19. 19.Best estimate of 718 + 327? (a) 1000 (b) 1200 (c) 800
  20. 20.Best estimate of 32 × 82? (a) 2400 (b) 24000 (c) 240
  21. 21.Best estimate of 788 + 627? (a) 1400 (b) 1600 (c) 1200
  22. 22.Best estimate of 673 + 778? (a) 1700 (b) 1300 (c) 1500
  23. 23.Best estimate of 81 × 46? (a) 40000 (b) 4000 (c) 400
  24. 24.Best estimate of 92 × 96? (a) 9000 (b) 900 (c) 90000
  25. 25.Best estimate of 76 × 69? (a) 56000 (b) 5600 (c) 560
  26. 26.Best estimate of 649 + 312? (a) 1100 (b) 700 (c) 900
  27. 27.Best estimate of 651 + 529? (a) 1400 (b) 1000 (c) 1200
  28. 28.Best estimate of 73 × 80? (a) 56000 (b) 560 (c) 5600
  29. 29.Best estimate of 79 × 79? (a) 6400 (b) 640 (c) 64000
  30. 30.Best estimate of 859 + 795? (a) 1900 (b) 1700 (c) 1500
  31. 31.Best estimate of 659 + 545? (a) 1200 (b) 1400 (c) 1000
  32. 32.Best estimate of 690 + 487? (a) 1200 (b) 1000 (c) 1400
  33. 33.Best estimate of 872 + 285? (a) 1400 (b) 1200 (c) 1000
  34. 34.Best estimate of 22 × 31? (a) 60 (b) 600 (c) 6000
  35. 35.Best estimate of 83 × 46? (a) 40000 (b) 4000 (c) 400
  36. 36.Best estimate of 437 + 807? (a) 1400 (b) 1000 (c) 1200
  37. 37.Best estimate of 190 + 621? (a) 600 (b) 1000 (c) 800
  38. 38.Best estimate of 37 × 77? (a) 3200 (b) 320 (c) 32000
  39. 39.Best estimate of 48 × 38? (a) 2000 (b) 200 (c) 20000
  40. 40.Best estimate of 69 × 66? (a) 490 (b) 4900 (c) 49000

Answer key

  1. 1800
  2. 4200
  3. 1200
  4. 900
  5. 6400
  6. 800
  7. 1000
  8. 600
  9. 1400
  10. 2400
  11. 1000
  12. 7200
  13. 5400
  14. 4200
  15. 800
  16. 3200
  17. 1800
  18. 700
  19. 1000
  20. 2400
  21. 1400
  22. 1500
  23. 4000
  24. 9000
  25. 5600
  26. 900
  27. 1200
  28. 5600
  29. 6400
  30. 1700
  31. 1200
  32. 1200
  33. 1200
  34. 600
  35. 4000
  36. 1200
  37. 800
  38. 3200
  39. 2000
  40. 4900

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