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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 177 · 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 20 × 59? (a) 12000 (b) 120 (c) 1200
  2. 2.Best estimate of 551 + 753? (a) 1600 (b) 1400 (c) 1200
  3. 3.Best estimate of 89 × 60? (a) 54000 (b) 540 (c) 5400
  4. 4.Best estimate of 833 + 687? (a) 1700 (b) 1300 (c) 1500
  5. 5.Best estimate of 56 × 97? (a) 600 (b) 60000 (c) 6000
  6. 6.Best estimate of 96 × 17? (a) 20000 (b) 2000 (c) 200
  7. 7.Best estimate of 216 + 577? (a) 800 (b) 600 (c) 1000
  8. 8.Best estimate of 23 × 40? (a) 8000 (b) 80 (c) 800
  9. 9.Best estimate of 16 × 44? (a) 800 (b) 80 (c) 8000
  10. 10.Best estimate of 68 × 22? (a) 14000 (b) 1400 (c) 140
  11. 11.Best estimate of 40 × 78? (a) 32000 (b) 3200 (c) 320
  12. 12.Best estimate of 235 + 356? (a) 400 (b) 600 (c) 800
  13. 13.Best estimate of 37 × 56? (a) 24000 (b) 2400 (c) 240
  14. 14.Best estimate of 260 + 426? (a) 500 (b) 900 (c) 700
  15. 15.Best estimate of 836 + 860? (a) 1700 (b) 1500 (c) 1900
  16. 16.Best estimate of 387 + 641? (a) 1200 (b) 1000 (c) 800
  17. 17.Best estimate of 762 + 694? (a) 1500 (b) 1700 (c) 1300
  18. 18.Best estimate of 12 × 26? (a) 300 (b) 3000 (c) 30
  19. 19.Best estimate of 553 + 860? (a) 1500 (b) 1300 (c) 1700
  20. 20.Best estimate of 16 × 26? (a) 600 (b) 6000 (c) 60
  21. 21.Best estimate of 233 + 144? (a) 100 (b) 300 (c) 500
  22. 22.Best estimate of 423 + 425? (a) 600 (b) 1000 (c) 800
  23. 23.Best estimate of 793 + 761? (a) 1600 (b) 1400 (c) 1800
  24. 24.Best estimate of 59 × 46? (a) 3000 (b) 30000 (c) 300
  25. 25.Best estimate of 517 + 632? (a) 1100 (b) 900 (c) 1300
  26. 26.Best estimate of 56 × 40? (a) 24000 (b) 240 (c) 2400
  27. 27.Best estimate of 317 + 149? (a) 400 (b) 200 (c) 600
  28. 28.Best estimate of 127 + 281? (a) 600 (b) 400 (c) 200
  29. 29.Best estimate of 86 × 47? (a) 4500 (b) 450 (c) 45000
  30. 30.Best estimate of 643 + 148? (a) 700 (b) 500 (c) 900
  31. 31.Best estimate of 14 × 74? (a) 7000 (b) 700 (c) 70
  32. 32.Best estimate of 615 + 865? (a) 1500 (b) 1300 (c) 1700
  33. 33.Best estimate of 295 + 306? (a) 400 (b) 800 (c) 600
  34. 34.Best estimate of 140 + 470? (a) 400 (b) 600 (c) 800
  35. 35.Best estimate of 56 × 24? (a) 1200 (b) 120 (c) 12000
  36. 36.Best estimate of 96 × 23? (a) 20000 (b) 200 (c) 2000
  37. 37.Best estimate of 241 + 407? (a) 800 (b) 600 (c) 400
  38. 38.Best estimate of 462 + 588? (a) 1100 (b) 1300 (c) 900
  39. 39.Best estimate of 13 × 50? (a) 5000 (b) 500 (c) 50
  40. 40.Best estimate of 26 × 90? (a) 270 (b) 27000 (c) 2700

Answer key

  1. 1200
  2. 1400
  3. 5400
  4. 1500
  5. 6000
  6. 2000
  7. 800
  8. 800
  9. 800
  10. 1400
  11. 3200
  12. 600
  13. 2400
  14. 700
  15. 1700
  16. 1000
  17. 1500
  18. 300
  19. 1500
  20. 600
  21. 300
  22. 800
  23. 1600
  24. 3000
  25. 1100
  26. 2400
  27. 400
  28. 400
  29. 4500
  30. 700
  31. 700
  32. 1500
  33. 600
  34. 600
  35. 1200
  36. 2000
  37. 600
  38. 1100
  39. 500
  40. 2700

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