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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 874 · 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 19 × 53? (a) 1000 (b) 10000 (c) 100
  2. 2.Best estimate of 854 + 786? (a) 1900 (b) 1500 (c) 1700
  3. 3.Best estimate of 607 + 734? (a) 1300 (b) 1500 (c) 1100
  4. 4.Best estimate of 859 + 288? (a) 1400 (b) 1200 (c) 1000
  5. 5.Best estimate of 443 + 786? (a) 1400 (b) 1000 (c) 1200
  6. 6.Best estimate of 29 × 69? (a) 2100 (b) 210 (c) 21000
  7. 7.Best estimate of 98 × 66? (a) 7000 (b) 70000 (c) 700
  8. 8.Best estimate of 865 + 170? (a) 1300 (b) 900 (c) 1100
  9. 9.Best estimate of 120 + 659? (a) 1000 (b) 600 (c) 800
  10. 10.Best estimate of 59 × 90? (a) 540 (b) 5400 (c) 54000
  11. 11.Best estimate of 472 + 125? (a) 600 (b) 800 (c) 400
  12. 12.Best estimate of 532 + 631? (a) 1100 (b) 900 (c) 1300
  13. 13.Best estimate of 50 × 36? (a) 2000 (b) 200 (c) 20000
  14. 14.Best estimate of 400 + 560? (a) 1200 (b) 1000 (c) 800
  15. 15.Best estimate of 738 + 705? (a) 1400 (b) 1600 (c) 1200
  16. 16.Best estimate of 33 × 79? (a) 2400 (b) 24000 (c) 240
  17. 17.Best estimate of 29 × 67? (a) 21000 (b) 210 (c) 2100
  18. 18.Best estimate of 660 + 297? (a) 1200 (b) 1000 (c) 800
  19. 19.Best estimate of 96 × 90? (a) 90000 (b) 900 (c) 9000
  20. 20.Best estimate of 620 + 579? (a) 1400 (b) 1000 (c) 1200
  21. 21.Best estimate of 166 + 724? (a) 900 (b) 700 (c) 1100
  22. 22.Best estimate of 14 × 87? (a) 90 (b) 900 (c) 9000
  23. 23.Best estimate of 20 × 63? (a) 12000 (b) 120 (c) 1200
  24. 24.Best estimate of 76 × 90? (a) 7200 (b) 720 (c) 72000
  25. 25.Best estimate of 26 × 23? (a) 60 (b) 600 (c) 6000
  26. 26.Best estimate of 423 + 794? (a) 1200 (b) 1400 (c) 1000
  27. 27.Best estimate of 29 × 61? (a) 18000 (b) 180 (c) 1800
  28. 28.Best estimate of 86 × 86? (a) 8100 (b) 810 (c) 81000
  29. 29.Best estimate of 292 + 525? (a) 600 (b) 800 (c) 1000
  30. 30.Best estimate of 32 × 92? (a) 270 (b) 27000 (c) 2700
  31. 31.Best estimate of 26 × 26? (a) 90 (b) 9000 (c) 900
  32. 32.Best estimate of 88 × 19? (a) 1800 (b) 18000 (c) 180
  33. 33.Best estimate of 30 × 19? (a) 600 (b) 6000 (c) 60
  34. 34.Best estimate of 26 × 33? (a) 9000 (b) 90 (c) 900
  35. 35.Best estimate of 187 + 455? (a) 700 (b) 900 (c) 500
  36. 36.Best estimate of 193 + 481? (a) 900 (b) 500 (c) 700
  37. 37.Best estimate of 62 × 70? (a) 42000 (b) 4200 (c) 420
  38. 38.Best estimate of 80 × 92? (a) 72000 (b) 720 (c) 7200
  39. 39.Best estimate of 568 + 373? (a) 1200 (b) 1000 (c) 800
  40. 40.Best estimate of 34 × 18? (a) 60 (b) 6000 (c) 600

Answer key

  1. 1000
  2. 1700
  3. 1300
  4. 1200
  5. 1200
  6. 2100
  7. 7000
  8. 1100
  9. 800
  10. 5400
  11. 600
  12. 1100
  13. 2000
  14. 1000
  15. 1400
  16. 2400
  17. 2100
  18. 1000
  19. 9000
  20. 1200
  21. 900
  22. 900
  23. 1200
  24. 7200
  25. 600
  26. 1200
  27. 1800
  28. 8100
  29. 800
  30. 2700
  31. 900
  32. 1800
  33. 600
  34. 900
  35. 700
  36. 700
  37. 4200
  38. 7200
  39. 1000
  40. 600

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