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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 659 · 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 469 + 824? (a) 1500 (b) 1300 (c) 1100
  2. 2.Best estimate of 476 + 817? (a) 1300 (b) 1100 (c) 1500
  3. 3.Best estimate of 92 × 58? (a) 5400 (b) 540 (c) 54000
  4. 4.Best estimate of 79 × 87? (a) 720 (b) 72000 (c) 7200
  5. 5.Best estimate of 83 × 60? (a) 48000 (b) 4800 (c) 480
  6. 6.Best estimate of 817 + 396? (a) 1000 (b) 1400 (c) 1200
  7. 7.Best estimate of 317 + 403? (a) 700 (b) 500 (c) 900
  8. 8.Best estimate of 24 × 73? (a) 1400 (b) 14000 (c) 140
  9. 9.Best estimate of 62 × 59? (a) 36000 (b) 3600 (c) 360
  10. 10.Best estimate of 18 × 92? (a) 180 (b) 18000 (c) 1800
  11. 11.Best estimate of 94 × 66? (a) 6300 (b) 63000 (c) 630
  12. 12.Best estimate of 94 × 28? (a) 2700 (b) 27000 (c) 270
  13. 13.Best estimate of 724 + 489? (a) 1200 (b) 1400 (c) 1000
  14. 14.Best estimate of 70 × 47? (a) 350 (b) 35000 (c) 3500
  15. 15.Best estimate of 371 + 241? (a) 400 (b) 800 (c) 600
  16. 16.Best estimate of 84 × 81? (a) 640 (b) 64000 (c) 6400
  17. 17.Best estimate of 53 × 52? (a) 2500 (b) 25000 (c) 250
  18. 18.Best estimate of 36 × 44? (a) 1600 (b) 16000 (c) 160
  19. 19.Best estimate of 36 × 71? (a) 2800 (b) 280 (c) 28000
  20. 20.Best estimate of 858 + 516? (a) 1600 (b) 1400 (c) 1200
  21. 21.Best estimate of 78 × 88? (a) 7200 (b) 720 (c) 72000
  22. 22.Best estimate of 79 × 67? (a) 56000 (b) 560 (c) 5600
  23. 23.Best estimate of 454 + 438? (a) 1100 (b) 900 (c) 700
  24. 24.Best estimate of 716 + 161? (a) 700 (b) 900 (c) 1100
  25. 25.Best estimate of 393 + 624? (a) 800 (b) 1000 (c) 1200
  26. 26.Best estimate of 616 + 438? (a) 1000 (b) 1200 (c) 800
  27. 27.Best estimate of 756 + 758? (a) 1600 (b) 1800 (c) 1400
  28. 28.Best estimate of 69 × 46? (a) 35000 (b) 3500 (c) 350
  29. 29.Best estimate of 290 + 801? (a) 1100 (b) 1300 (c) 900
  30. 30.Best estimate of 98 × 42? (a) 4000 (b) 40000 (c) 400
  31. 31.Best estimate of 751 + 859? (a) 1500 (b) 1700 (c) 1900
  32. 32.Best estimate of 84 × 49? (a) 4000 (b) 400 (c) 40000
  33. 33.Best estimate of 64 × 41? (a) 2400 (b) 240 (c) 24000
  34. 34.Best estimate of 22 × 34? (a) 600 (b) 60 (c) 6000
  35. 35.Best estimate of 846 + 383? (a) 1000 (b) 1400 (c) 1200
  36. 36.Best estimate of 830 + 563? (a) 1400 (b) 1200 (c) 1600
  37. 37.Best estimate of 16 × 22? (a) 400 (b) 4000 (c) 40
  38. 38.Best estimate of 630 + 716? (a) 1300 (b) 1500 (c) 1100
  39. 39.Best estimate of 12 × 30? (a) 30 (b) 3000 (c) 300
  40. 40.Best estimate of 587 + 810? (a) 1200 (b) 1600 (c) 1400

Answer key

  1. 1300
  2. 1300
  3. 5400
  4. 7200
  5. 4800
  6. 1200
  7. 700
  8. 1400
  9. 3600
  10. 1800
  11. 6300
  12. 2700
  13. 1200
  14. 3500
  15. 600
  16. 6400
  17. 2500
  18. 1600
  19. 2800
  20. 1400
  21. 7200
  22. 5600
  23. 900
  24. 900
  25. 1000
  26. 1000
  27. 1600
  28. 3500
  29. 1100
  30. 4000
  31. 1700
  32. 4000
  33. 2400
  34. 600
  35. 1200
  36. 1400
  37. 400
  38. 1300
  39. 300
  40. 1400

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