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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 608 · 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 42 × 66? (a) 28000 (b) 280 (c) 2800
  2. 2.Best estimate of 93 × 68? (a) 63000 (b) 630 (c) 6300
  3. 3.Best estimate of 710 + 264? (a) 1200 (b) 1000 (c) 800
  4. 4.Best estimate of 22 × 31? (a) 600 (b) 60 (c) 6000
  5. 5.Best estimate of 84 × 68? (a) 560 (b) 56000 (c) 5600
  6. 6.Best estimate of 14 × 76? (a) 800 (b) 80 (c) 8000
  7. 7.Best estimate of 12 × 56? (a) 6000 (b) 60 (c) 600
  8. 8.Best estimate of 40 × 16? (a) 800 (b) 8000 (c) 80
  9. 9.Best estimate of 660 + 436? (a) 900 (b) 1100 (c) 1300
  10. 10.Best estimate of 98 × 16? (a) 200 (b) 2000 (c) 20000
  11. 11.Best estimate of 20 × 73? (a) 14000 (b) 140 (c) 1400
  12. 12.Best estimate of 212 + 165? (a) 400 (b) 600 (c) 200
  13. 13.Best estimate of 214 + 392? (a) 600 (b) 800 (c) 400
  14. 14.Best estimate of 29 × 96? (a) 300 (b) 3000 (c) 30000
  15. 15.Best estimate of 22 × 24? (a) 4000 (b) 400 (c) 40
  16. 16.Best estimate of 456 + 776? (a) 1500 (b) 1100 (c) 1300
  17. 17.Best estimate of 527 + 668? (a) 1400 (b) 1000 (c) 1200
  18. 18.Best estimate of 364 + 744? (a) 900 (b) 1300 (c) 1100
  19. 19.Best estimate of 773 + 335? (a) 1100 (b) 900 (c) 1300
  20. 20.Best estimate of 718 + 585? (a) 1300 (b) 1500 (c) 1100
  21. 21.Best estimate of 27 × 26? (a) 900 (b) 9000 (c) 90
  22. 22.Best estimate of 88 × 17? (a) 18000 (b) 180 (c) 1800
  23. 23.Best estimate of 60 × 16? (a) 12000 (b) 1200 (c) 120
  24. 24.Best estimate of 57 × 64? (a) 360 (b) 3600 (c) 36000
  25. 25.Best estimate of 58 × 92? (a) 540 (b) 54000 (c) 5400
  26. 26.Best estimate of 26 × 59? (a) 1800 (b) 180 (c) 18000
  27. 27.Best estimate of 249 + 834? (a) 1000 (b) 800 (c) 1200
  28. 28.Best estimate of 834 + 809? (a) 1600 (b) 1800 (c) 1400
  29. 29.Best estimate of 552 + 149? (a) 900 (b) 700 (c) 500
  30. 30.Best estimate of 66 × 44? (a) 2800 (b) 28000 (c) 280
  31. 31.Best estimate of 746 + 799? (a) 1300 (b) 1700 (c) 1500
  32. 32.Best estimate of 451 + 625? (a) 1300 (b) 900 (c) 1100
  33. 33.Best estimate of 62 × 97? (a) 60000 (b) 6000 (c) 600
  34. 34.Best estimate of 431 + 630? (a) 1200 (b) 1000 (c) 800
  35. 35.Best estimate of 67 × 36? (a) 2800 (b) 28000 (c) 280
  36. 36.Best estimate of 817 + 820? (a) 1400 (b) 1600 (c) 1800
  37. 37.Best estimate of 70 × 26? (a) 21000 (b) 2100 (c) 210
  38. 38.Best estimate of 768 + 320? (a) 1300 (b) 900 (c) 1100
  39. 39.Best estimate of 196 + 590? (a) 800 (b) 1000 (c) 600
  40. 40.Best estimate of 91 × 78? (a) 72000 (b) 720 (c) 7200

Answer key

  1. 2800
  2. 6300
  3. 1000
  4. 600
  5. 5600
  6. 800
  7. 600
  8. 800
  9. 1100
  10. 2000
  11. 1400
  12. 400
  13. 600
  14. 3000
  15. 400
  16. 1300
  17. 1200
  18. 1100
  19. 1100
  20. 1300
  21. 900
  22. 1800
  23. 1200
  24. 3600
  25. 5400
  26. 1800
  27. 1000
  28. 1600
  29. 700
  30. 2800
  31. 1500
  32. 1100
  33. 6000
  34. 1000
  35. 2800
  36. 1600
  37. 2100
  38. 1100
  39. 800
  40. 7200

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