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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 823 · 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 84 × 24? (a) 160 (b) 1600 (c) 16000
  2. 2.Best estimate of 862 + 673? (a) 1800 (b) 1600 (c) 1400
  3. 3.Best estimate of 262 + 310? (a) 400 (b) 800 (c) 600
  4. 4.Best estimate of 37 × 19? (a) 80 (b) 800 (c) 8000
  5. 5.Best estimate of 28 × 30? (a) 90 (b) 9000 (c) 900
  6. 6.Best estimate of 852 + 153? (a) 1300 (b) 900 (c) 1100
  7. 7.Best estimate of 66 × 46? (a) 35000 (b) 350 (c) 3500
  8. 8.Best estimate of 328 + 727? (a) 1200 (b) 800 (c) 1000
  9. 9.Best estimate of 57 × 88? (a) 54000 (b) 540 (c) 5400
  10. 10.Best estimate of 60 × 98? (a) 6000 (b) 60000 (c) 600
  11. 11.Best estimate of 847 + 291? (a) 1300 (b) 1100 (c) 900
  12. 12.Best estimate of 488 + 696? (a) 1200 (b) 1400 (c) 1000
  13. 13.Best estimate of 16 × 34? (a) 60 (b) 600 (c) 6000
  14. 14.Best estimate of 86 × 81? (a) 720 (b) 72000 (c) 7200
  15. 15.Best estimate of 94 × 53? (a) 4500 (b) 45000 (c) 450
  16. 16.Best estimate of 599 + 206? (a) 1000 (b) 600 (c) 800
  17. 17.Best estimate of 97 × 63? (a) 600 (b) 60000 (c) 6000
  18. 18.Best estimate of 822 + 220? (a) 800 (b) 1200 (c) 1000
  19. 19.Best estimate of 83 × 38? (a) 3200 (b) 32000 (c) 320
  20. 20.Best estimate of 749 + 868? (a) 1800 (b) 1600 (c) 1400
  21. 21.Best estimate of 87 × 51? (a) 4500 (b) 45000 (c) 450
  22. 22.Best estimate of 64 × 22? (a) 120 (b) 1200 (c) 12000
  23. 23.Best estimate of 83 × 36? (a) 32000 (b) 320 (c) 3200
  24. 24.Best estimate of 46 × 61? (a) 3000 (b) 300 (c) 30000
  25. 25.Best estimate of 274 + 200? (a) 300 (b) 700 (c) 500
  26. 26.Best estimate of 709 + 149? (a) 1000 (b) 600 (c) 800
  27. 27.Best estimate of 81 × 57? (a) 48000 (b) 480 (c) 4800
  28. 28.Best estimate of 843 + 175? (a) 1000 (b) 800 (c) 1200
  29. 29.Best estimate of 766 + 446? (a) 1400 (b) 1000 (c) 1200
  30. 30.Best estimate of 47 × 44? (a) 2000 (b) 200 (c) 20000
  31. 31.Best estimate of 417 + 694? (a) 1300 (b) 1100 (c) 900
  32. 32.Best estimate of 92 × 36? (a) 3600 (b) 360 (c) 36000
  33. 33.Best estimate of 97 × 14? (a) 1000 (b) 100 (c) 10000
  34. 34.Best estimate of 60 × 46? (a) 3000 (b) 30000 (c) 300
  35. 35.Best estimate of 616 + 299? (a) 900 (b) 700 (c) 1100
  36. 36.Best estimate of 90 × 31? (a) 270 (b) 27000 (c) 2700
  37. 37.Best estimate of 43 × 43? (a) 160 (b) 16000 (c) 1600
  38. 38.Best estimate of 43 × 82? (a) 3200 (b) 32000 (c) 320
  39. 39.Best estimate of 503 + 181? (a) 500 (b) 700 (c) 900
  40. 40.Best estimate of 559 + 187? (a) 1000 (b) 800 (c) 600

Answer key

  1. 1600
  2. 1600
  3. 600
  4. 800
  5. 900
  6. 1100
  7. 3500
  8. 1000
  9. 5400
  10. 6000
  11. 1100
  12. 1200
  13. 600
  14. 7200
  15. 4500
  16. 800
  17. 6000
  18. 1000
  19. 3200
  20. 1600
  21. 4500
  22. 1200
  23. 3200
  24. 3000
  25. 500
  26. 800
  27. 4800
  28. 1000
  29. 1200
  30. 2000
  31. 1100
  32. 3600
  33. 1000
  34. 3000
  35. 900
  36. 2700
  37. 1600
  38. 3200
  39. 700
  40. 800

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