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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 832 · 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 159 + 307? (a) 700 (b) 300 (c) 500
  2. 2.Best estimate of 83 × 66? (a) 5600 (b) 56000 (c) 560
  3. 3.Best estimate of 327 + 190? (a) 500 (b) 700 (c) 300
  4. 4.Best estimate of 12 × 59? (a) 600 (b) 60 (c) 6000
  5. 5.Best estimate of 96 × 28? (a) 30000 (b) 300 (c) 3000
  6. 6.Best estimate of 73 × 72? (a) 490 (b) 4900 (c) 49000
  7. 7.Best estimate of 280 + 772? (a) 1100 (b) 900 (c) 1300
  8. 8.Best estimate of 794 + 536? (a) 1100 (b) 1300 (c) 1500
  9. 9.Best estimate of 554 + 478? (a) 1300 (b) 1100 (c) 900
  10. 10.Best estimate of 565 + 244? (a) 1000 (b) 600 (c) 800
  11. 11.Best estimate of 21 × 66? (a) 1400 (b) 140 (c) 14000
  12. 12.Best estimate of 246 + 216? (a) 600 (b) 200 (c) 400
  13. 13.Best estimate of 77 × 71? (a) 560 (b) 56000 (c) 5600
  14. 14.Best estimate of 446 + 641? (a) 1000 (b) 1200 (c) 800
  15. 15.Best estimate of 144 + 617? (a) 700 (b) 900 (c) 500
  16. 16.Best estimate of 23 × 78? (a) 160 (b) 1600 (c) 16000
  17. 17.Best estimate of 60 × 91? (a) 54000 (b) 5400 (c) 540
  18. 18.Best estimate of 766 + 582? (a) 1200 (b) 1600 (c) 1400
  19. 19.Best estimate of 67 × 43? (a) 28000 (b) 280 (c) 2800
  20. 20.Best estimate of 169 + 311? (a) 500 (b) 700 (c) 300
  21. 21.Best estimate of 712 + 851? (a) 1400 (b) 1600 (c) 1800
  22. 22.Best estimate of 37 × 31? (a) 120 (b) 1200 (c) 12000
  23. 23.Best estimate of 18 × 54? (a) 10000 (b) 1000 (c) 100
  24. 24.Best estimate of 48 × 49? (a) 2500 (b) 250 (c) 25000
  25. 25.Best estimate of 299 + 280? (a) 800 (b) 400 (c) 600
  26. 26.Best estimate of 71 × 56? (a) 42000 (b) 4200 (c) 420
  27. 27.Best estimate of 386 + 300? (a) 500 (b) 900 (c) 700
  28. 28.Best estimate of 41 × 49? (a) 200 (b) 2000 (c) 20000
  29. 29.Best estimate of 64 × 59? (a) 360 (b) 3600 (c) 36000
  30. 30.Best estimate of 18 × 22? (a) 4000 (b) 40 (c) 400
  31. 31.Best estimate of 237 + 600? (a) 1000 (b) 800 (c) 600
  32. 32.Best estimate of 725 + 256? (a) 1200 (b) 1000 (c) 800
  33. 33.Best estimate of 51 × 77? (a) 40000 (b) 400 (c) 4000
  34. 34.Best estimate of 590 + 685? (a) 1500 (b) 1100 (c) 1300
  35. 35.Best estimate of 53 × 56? (a) 30000 (b) 300 (c) 3000
  36. 36.Best estimate of 318 + 381? (a) 500 (b) 900 (c) 700
  37. 37.Best estimate of 74 × 92? (a) 630 (b) 63000 (c) 6300
  38. 38.Best estimate of 83 × 36? (a) 320 (b) 3200 (c) 32000
  39. 39.Best estimate of 12 × 17? (a) 2000 (b) 20 (c) 200
  40. 40.Best estimate of 91 × 40? (a) 3600 (b) 360 (c) 36000

Answer key

  1. 500
  2. 5600
  3. 500
  4. 600
  5. 3000
  6. 4900
  7. 1100
  8. 1300
  9. 1100
  10. 800
  11. 1400
  12. 400
  13. 5600
  14. 1000
  15. 700
  16. 1600
  17. 5400
  18. 1400
  19. 2800
  20. 500
  21. 1600
  22. 1200
  23. 1000
  24. 2500
  25. 600
  26. 4200
  27. 700
  28. 2000
  29. 3600
  30. 400
  31. 800
  32. 1000
  33. 4000
  34. 1300
  35. 3000
  36. 700
  37. 6300
  38. 3200
  39. 200
  40. 3600

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