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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 124 · 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 354 + 869? (a) 1500 (b) 1300 (c) 1100
  2. 2.Best estimate of 77 × 78? (a) 640 (b) 6400 (c) 64000
  3. 3.Best estimate of 79 × 49? (a) 4000 (b) 40000 (c) 400
  4. 4.Best estimate of 523 + 455? (a) 1000 (b) 1200 (c) 800
  5. 5.Best estimate of 159 + 572? (a) 800 (b) 600 (c) 1000
  6. 6.Best estimate of 19 × 26? (a) 600 (b) 6000 (c) 60
  7. 7.Best estimate of 292 + 426? (a) 700 (b) 900 (c) 500
  8. 8.Best estimate of 28 × 66? (a) 210 (b) 21000 (c) 2100
  9. 9.Best estimate of 473 + 434? (a) 1100 (b) 900 (c) 700
  10. 10.Best estimate of 484 + 656? (a) 1200 (b) 1400 (c) 1000
  11. 11.Best estimate of 56 × 66? (a) 420 (b) 42000 (c) 4200
  12. 12.Best estimate of 617 + 813? (a) 1600 (b) 1200 (c) 1400
  13. 13.Best estimate of 61 × 34? (a) 18000 (b) 1800 (c) 180
  14. 14.Best estimate of 87 × 82? (a) 720 (b) 72000 (c) 7200
  15. 15.Best estimate of 673 + 758? (a) 1300 (b) 1500 (c) 1700
  16. 16.Best estimate of 71 × 60? (a) 420 (b) 42000 (c) 4200
  17. 17.Best estimate of 36 × 87? (a) 3600 (b) 360 (c) 36000
  18. 18.Best estimate of 590 + 510? (a) 1300 (b) 1100 (c) 900
  19. 19.Best estimate of 514 + 122? (a) 600 (b) 400 (c) 800
  20. 20.Best estimate of 84 × 57? (a) 480 (b) 4800 (c) 48000
  21. 21.Best estimate of 157 + 207? (a) 400 (b) 600 (c) 200
  22. 22.Best estimate of 673 + 789? (a) 1500 (b) 1300 (c) 1700
  23. 23.Best estimate of 66 × 44? (a) 2800 (b) 28000 (c) 280
  24. 24.Best estimate of 16 × 12? (a) 2000 (b) 200 (c) 20
  25. 25.Best estimate of 54 × 22? (a) 1000 (b) 100 (c) 10000
  26. 26.Best estimate of 279 + 264? (a) 600 (b) 400 (c) 800
  27. 27.Best estimate of 701 + 231? (a) 700 (b) 1100 (c) 900
  28. 28.Best estimate of 157 + 433? (a) 600 (b) 400 (c) 800
  29. 29.Best estimate of 59 × 52? (a) 30000 (b) 3000 (c) 300
  30. 30.Best estimate of 71 × 44? (a) 2800 (b) 280 (c) 28000
  31. 31.Best estimate of 545 + 120? (a) 600 (b) 800 (c) 400
  32. 32.Best estimate of 86 × 93? (a) 8100 (b) 810 (c) 81000
  33. 33.Best estimate of 94 × 54? (a) 45000 (b) 450 (c) 4500
  34. 34.Best estimate of 174 + 594? (a) 800 (b) 1000 (c) 600
  35. 35.Best estimate of 76 × 42? (a) 3200 (b) 32000 (c) 320
  36. 36.Best estimate of 483 + 343? (a) 1000 (b) 600 (c) 800
  37. 37.Best estimate of 97 × 88? (a) 900 (b) 9000 (c) 90000
  38. 38.Best estimate of 438 + 740? (a) 1100 (b) 900 (c) 1300
  39. 39.Best estimate of 54 × 36? (a) 2000 (b) 20000 (c) 200
  40. 40.Best estimate of 83 × 47? (a) 40000 (b) 4000 (c) 400

Answer key

  1. 1300
  2. 6400
  3. 4000
  4. 1000
  5. 800
  6. 600
  7. 700
  8. 2100
  9. 900
  10. 1200
  11. 4200
  12. 1400
  13. 1800
  14. 7200
  15. 1500
  16. 4200
  17. 3600
  18. 1100
  19. 600
  20. 4800
  21. 400
  22. 1500
  23. 2800
  24. 200
  25. 1000
  26. 600
  27. 900
  28. 600
  29. 3000
  30. 2800
  31. 600
  32. 8100
  33. 4500
  34. 800
  35. 3200
  36. 800
  37. 9000
  38. 1100
  39. 2000
  40. 4000

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