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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 773 · 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 64 × 88? (a) 540 (b) 5400 (c) 54000
  2. 2.Best estimate of 212 + 307? (a) 700 (b) 300 (c) 500
  3. 3.Best estimate of 89 × 46? (a) 4500 (b) 45000 (c) 450
  4. 4.Best estimate of 799 + 329? (a) 1100 (b) 1300 (c) 900
  5. 5.Best estimate of 29 × 13? (a) 30 (b) 300 (c) 3000
  6. 6.Best estimate of 29 × 14? (a) 30 (b) 3000 (c) 300
  7. 7.Best estimate of 63 × 51? (a) 300 (b) 3000 (c) 30000
  8. 8.Best estimate of 30 × 24? (a) 6000 (b) 60 (c) 600
  9. 9.Best estimate of 61 × 47? (a) 3000 (b) 30000 (c) 300
  10. 10.Best estimate of 81 × 31? (a) 240 (b) 2400 (c) 24000
  11. 11.Best estimate of 483 + 434? (a) 1100 (b) 900 (c) 700
  12. 12.Best estimate of 13 × 52? (a) 5000 (b) 50 (c) 500
  13. 13.Best estimate of 27 × 49? (a) 1500 (b) 15000 (c) 150
  14. 14.Best estimate of 516 + 216? (a) 700 (b) 500 (c) 900
  15. 15.Best estimate of 36 × 29? (a) 120 (b) 12000 (c) 1200
  16. 16.Best estimate of 443 + 597? (a) 1200 (b) 1000 (c) 800
  17. 17.Best estimate of 77 × 33? (a) 2400 (b) 24000 (c) 240
  18. 18.Best estimate of 501 + 649? (a) 900 (b) 1100 (c) 1300
  19. 19.Best estimate of 505 + 728? (a) 1400 (b) 1200 (c) 1000
  20. 20.Best estimate of 689 + 745? (a) 1600 (b) 1200 (c) 1400
  21. 21.Best estimate of 61 × 46? (a) 3000 (b) 30000 (c) 300
  22. 22.Best estimate of 18 × 61? (a) 120 (b) 1200 (c) 12000
  23. 23.Best estimate of 871 + 690? (a) 1600 (b) 1400 (c) 1800
  24. 24.Best estimate of 299 + 558? (a) 900 (b) 1100 (c) 700
  25. 25.Best estimate of 753 + 473? (a) 1500 (b) 1100 (c) 1300
  26. 26.Best estimate of 17 × 57? (a) 1200 (b) 12000 (c) 120
  27. 27.Best estimate of 27 × 89? (a) 27000 (b) 2700 (c) 270
  28. 28.Best estimate of 56 × 19? (a) 120 (b) 1200 (c) 12000
  29. 29.Best estimate of 439 + 123? (a) 300 (b) 500 (c) 700
  30. 30.Best estimate of 774 + 220? (a) 1200 (b) 1000 (c) 800
  31. 31.Best estimate of 46 × 26? (a) 150 (b) 1500 (c) 15000
  32. 32.Best estimate of 400 + 343? (a) 700 (b) 500 (c) 900
  33. 33.Best estimate of 684 + 808? (a) 1700 (b) 1500 (c) 1300
  34. 34.Best estimate of 47 × 36? (a) 2000 (b) 20000 (c) 200
  35. 35.Best estimate of 508 + 532? (a) 1200 (b) 1000 (c) 800
  36. 36.Best estimate of 13 × 97? (a) 10000 (b) 1000 (c) 100
  37. 37.Best estimate of 420 + 575? (a) 1200 (b) 800 (c) 1000
  38. 38.Best estimate of 37 × 43? (a) 16000 (b) 160 (c) 1600
  39. 39.Best estimate of 22 × 53? (a) 10000 (b) 1000 (c) 100
  40. 40.Best estimate of 49 × 76? (a) 4000 (b) 40000 (c) 400

Answer key

  1. 5400
  2. 500
  3. 4500
  4. 1100
  5. 300
  6. 300
  7. 3000
  8. 600
  9. 3000
  10. 2400
  11. 900
  12. 500
  13. 1500
  14. 700
  15. 1200
  16. 1000
  17. 2400
  18. 1100
  19. 1200
  20. 1400
  21. 3000
  22. 1200
  23. 1600
  24. 900
  25. 1300
  26. 1200
  27. 2700
  28. 1200
  29. 500
  30. 1000
  31. 1500
  32. 700
  33. 1500
  34. 2000
  35. 1000
  36. 1000
  37. 1000
  38. 1600
  39. 1000
  40. 4000

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