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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 825 · 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 776 + 496? (a) 1300 (b) 1100 (c) 1500
  2. 2.Best estimate of 49 × 60? (a) 300 (b) 3000 (c) 30000
  3. 3.Best estimate of 78 × 98? (a) 800 (b) 80000 (c) 8000
  4. 4.Best estimate of 33 × 82? (a) 24000 (b) 2400 (c) 240
  5. 5.Best estimate of 69 × 44? (a) 2800 (b) 280 (c) 28000
  6. 6.Best estimate of 478 + 758? (a) 1500 (b) 1100 (c) 1300
  7. 7.Best estimate of 468 + 408? (a) 700 (b) 900 (c) 1100
  8. 8.Best estimate of 170 + 386? (a) 400 (b) 600 (c) 800
  9. 9.Best estimate of 428 + 135? (a) 300 (b) 700 (c) 500
  10. 10.Best estimate of 68 × 47? (a) 3500 (b) 350 (c) 35000
  11. 11.Best estimate of 252 + 219? (a) 700 (b) 500 (c) 300
  12. 12.Best estimate of 614 + 283? (a) 1100 (b) 700 (c) 900
  13. 13.Best estimate of 821 + 877? (a) 1900 (b) 1700 (c) 1500
  14. 14.Best estimate of 191 + 440? (a) 400 (b) 600 (c) 800
  15. 15.Best estimate of 651 + 415? (a) 900 (b) 1100 (c) 1300
  16. 16.Best estimate of 46 × 58? (a) 30000 (b) 300 (c) 3000
  17. 17.Best estimate of 30 × 47? (a) 15000 (b) 1500 (c) 150
  18. 18.Best estimate of 206 + 530? (a) 500 (b) 900 (c) 700
  19. 19.Best estimate of 642 + 369? (a) 1000 (b) 1200 (c) 800
  20. 20.Best estimate of 131 + 847? (a) 700 (b) 1100 (c) 900
  21. 21.Best estimate of 79 × 18? (a) 1600 (b) 16000 (c) 160
  22. 22.Best estimate of 97 × 73? (a) 7000 (b) 700 (c) 70000
  23. 23.Best estimate of 57 × 92? (a) 54000 (b) 5400 (c) 540
  24. 24.Best estimate of 738 + 583? (a) 1300 (b) 1500 (c) 1100
  25. 25.Best estimate of 737 + 669? (a) 1600 (b) 1200 (c) 1400
  26. 26.Best estimate of 149 + 564? (a) 500 (b) 900 (c) 700
  27. 27.Best estimate of 37 × 16? (a) 800 (b) 8000 (c) 80
  28. 28.Best estimate of 332 + 412? (a) 900 (b) 700 (c) 500
  29. 29.Best estimate of 88 × 56? (a) 54000 (b) 540 (c) 5400
  30. 30.Best estimate of 36 × 97? (a) 400 (b) 4000 (c) 40000
  31. 31.Best estimate of 736 + 247? (a) 1100 (b) 700 (c) 900
  32. 32.Best estimate of 73 × 28? (a) 2100 (b) 21000 (c) 210
  33. 33.Best estimate of 33 × 69? (a) 2100 (b) 210 (c) 21000
  34. 34.Best estimate of 86 × 12? (a) 900 (b) 9000 (c) 90
  35. 35.Best estimate of 71 × 29? (a) 21000 (b) 2100 (c) 210
  36. 36.Best estimate of 851 + 204? (a) 900 (b) 1300 (c) 1100
  37. 37.Best estimate of 225 + 200? (a) 400 (b) 600 (c) 200
  38. 38.Best estimate of 82 × 88? (a) 72000 (b) 7200 (c) 720
  39. 39.Best estimate of 96 × 29? (a) 30000 (b) 3000 (c) 300
  40. 40.Best estimate of 599 + 387? (a) 1200 (b) 1000 (c) 800

Answer key

  1. 1300
  2. 3000
  3. 8000
  4. 2400
  5. 2800
  6. 1300
  7. 900
  8. 600
  9. 500
  10. 3500
  11. 500
  12. 900
  13. 1700
  14. 600
  15. 1100
  16. 3000
  17. 1500
  18. 700
  19. 1000
  20. 900
  21. 1600
  22. 7000
  23. 5400
  24. 1300
  25. 1400
  26. 700
  27. 800
  28. 700
  29. 5400
  30. 4000
  31. 900
  32. 2100
  33. 2100
  34. 900
  35. 2100
  36. 1100
  37. 400
  38. 7200
  39. 3000
  40. 1000

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