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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 750 · 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 90 × 64? (a) 540 (b) 5400 (c) 54000
  2. 2.Best estimate of 69 × 36? (a) 28000 (b) 2800 (c) 280
  3. 3.Best estimate of 513 + 255? (a) 800 (b) 1000 (c) 600
  4. 4.Best estimate of 462 + 201? (a) 900 (b) 700 (c) 500
  5. 5.Best estimate of 90 × 21? (a) 1800 (b) 18000 (c) 180
  6. 6.Best estimate of 28 × 96? (a) 3000 (b) 300 (c) 30000
  7. 7.Best estimate of 44 × 16? (a) 800 (b) 80 (c) 8000
  8. 8.Best estimate of 52 × 54? (a) 25000 (b) 250 (c) 2500
  9. 9.Best estimate of 318 + 330? (a) 600 (b) 400 (c) 800
  10. 10.Best estimate of 394 + 838? (a) 1000 (b) 1200 (c) 1400
  11. 11.Best estimate of 57 × 93? (a) 54000 (b) 540 (c) 5400
  12. 12.Best estimate of 567 + 342? (a) 1100 (b) 900 (c) 700
  13. 13.Best estimate of 86 × 66? (a) 630 (b) 6300 (c) 63000
  14. 14.Best estimate of 89 × 16? (a) 18000 (b) 180 (c) 1800
  15. 15.Best estimate of 93 × 41? (a) 3600 (b) 360 (c) 36000
  16. 16.Best estimate of 16 × 84? (a) 1600 (b) 16000 (c) 160
  17. 17.Best estimate of 79 × 66? (a) 56000 (b) 560 (c) 5600
  18. 18.Best estimate of 372 + 391? (a) 800 (b) 600 (c) 1000
  19. 19.Best estimate of 601 + 880? (a) 1500 (b) 1700 (c) 1300
  20. 20.Best estimate of 416 + 755? (a) 1200 (b) 1000 (c) 1400
  21. 21.Best estimate of 351 + 530? (a) 700 (b) 1100 (c) 900
  22. 22.Best estimate of 526 + 577? (a) 1300 (b) 1100 (c) 900
  23. 23.Best estimate of 26 × 14? (a) 30 (b) 300 (c) 3000
  24. 24.Best estimate of 246 + 806? (a) 1000 (b) 1200 (c) 800
  25. 25.Best estimate of 96 × 96? (a) 1000 (b) 10000 (c) 100000
  26. 26.Best estimate of 289 + 725? (a) 1000 (b) 1200 (c) 800
  27. 27.Best estimate of 16 × 71? (a) 14000 (b) 1400 (c) 140
  28. 28.Best estimate of 28 × 32? (a) 9000 (b) 90 (c) 900
  29. 29.Best estimate of 318 + 277? (a) 800 (b) 400 (c) 600
  30. 30.Best estimate of 126 + 194? (a) 300 (b) 500 (c) 100
  31. 31.Best estimate of 86 × 32? (a) 2700 (b) 27000 (c) 270
  32. 32.Best estimate of 21 × 72? (a) 140 (b) 1400 (c) 14000
  33. 33.Best estimate of 328 + 865? (a) 1200 (b) 1400 (c) 1000
  34. 34.Best estimate of 26 × 76? (a) 24000 (b) 240 (c) 2400
  35. 35.Best estimate of 547 + 833? (a) 1100 (b) 1300 (c) 1500
  36. 36.Best estimate of 73 × 69? (a) 4900 (b) 49000 (c) 490
  37. 37.Best estimate of 279 + 651? (a) 800 (b) 1000 (c) 1200
  38. 38.Best estimate of 90 × 40? (a) 360 (b) 3600 (c) 36000
  39. 39.Best estimate of 52 × 37? (a) 2000 (b) 200 (c) 20000
  40. 40.Best estimate of 132 + 296? (a) 400 (b) 600 (c) 200

Answer key

  1. 5400
  2. 2800
  3. 800
  4. 700
  5. 1800
  6. 3000
  7. 800
  8. 2500
  9. 600
  10. 1200
  11. 5400
  12. 900
  13. 6300
  14. 1800
  15. 3600
  16. 1600
  17. 5600
  18. 800
  19. 1500
  20. 1200
  21. 900
  22. 1100
  23. 300
  24. 1000
  25. 10000
  26. 1000
  27. 1400
  28. 900
  29. 600
  30. 300
  31. 2700
  32. 1400
  33. 1200
  34. 2400
  35. 1300
  36. 4900
  37. 1000
  38. 3600
  39. 2000
  40. 400

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