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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 201 · 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 22 × 66? (a) 1400 (b) 140 (c) 14000
  2. 2.Best estimate of 60 × 98? (a) 600 (b) 60000 (c) 6000
  3. 3.Best estimate of 529 + 353? (a) 900 (b) 1100 (c) 700
  4. 4.Best estimate of 418 + 468? (a) 900 (b) 700 (c) 1100
  5. 5.Best estimate of 336 + 152? (a) 500 (b) 300 (c) 700
  6. 6.Best estimate of 43 × 12? (a) 4000 (b) 400 (c) 40
  7. 7.Best estimate of 87 × 59? (a) 5400 (b) 540 (c) 54000
  8. 8.Best estimate of 19 × 86? (a) 1800 (b) 180 (c) 18000
  9. 9.Best estimate of 414 + 441? (a) 1000 (b) 800 (c) 600
  10. 10.Best estimate of 56 × 63? (a) 3600 (b) 360 (c) 36000
  11. 11.Best estimate of 200 + 302? (a) 700 (b) 500 (c) 300
  12. 12.Best estimate of 36 × 44? (a) 1600 (b) 16000 (c) 160
  13. 13.Best estimate of 657 + 837? (a) 1300 (b) 1500 (c) 1700
  14. 14.Best estimate of 67 × 66? (a) 490 (b) 49000 (c) 4900
  15. 15.Best estimate of 742 + 351? (a) 1300 (b) 1100 (c) 900
  16. 16.Best estimate of 68 × 43? (a) 280 (b) 2800 (c) 28000
  17. 17.Best estimate of 458 + 403? (a) 700 (b) 900 (c) 1100
  18. 18.Best estimate of 14 × 64? (a) 600 (b) 60 (c) 6000
  19. 19.Best estimate of 21 × 46? (a) 1000 (b) 10000 (c) 100
  20. 20.Best estimate of 724 + 857? (a) 1800 (b) 1400 (c) 1600
  21. 21.Best estimate of 19 × 76? (a) 1600 (b) 16000 (c) 160
  22. 22.Best estimate of 245 + 599? (a) 800 (b) 600 (c) 1000
  23. 23.Best estimate of 58 × 89? (a) 54000 (b) 540 (c) 5400
  24. 24.Best estimate of 71 × 14? (a) 700 (b) 70 (c) 7000
  25. 25.Best estimate of 751 + 247? (a) 1000 (b) 1200 (c) 800
  26. 26.Best estimate of 29 × 14? (a) 3000 (b) 300 (c) 30
  27. 27.Best estimate of 591 + 206? (a) 1000 (b) 600 (c) 800
  28. 28.Best estimate of 655 + 624? (a) 1300 (b) 1500 (c) 1100
  29. 29.Best estimate of 80 × 39? (a) 3200 (b) 320 (c) 32000
  30. 30.Best estimate of 56 × 90? (a) 5400 (b) 540 (c) 54000
  31. 31.Best estimate of 727 + 654? (a) 1200 (b) 1600 (c) 1400
  32. 32.Best estimate of 32 × 61? (a) 180 (b) 1800 (c) 18000
  33. 33.Best estimate of 39 × 51? (a) 2000 (b) 200 (c) 20000
  34. 34.Best estimate of 780 + 243? (a) 1200 (b) 1000 (c) 800
  35. 35.Best estimate of 76 × 26? (a) 24000 (b) 2400 (c) 240
  36. 36.Best estimate of 340 + 126? (a) 600 (b) 400 (c) 200
  37. 37.Best estimate of 270 + 530? (a) 600 (b) 800 (c) 1000
  38. 38.Best estimate of 86 × 30? (a) 2700 (b) 27000 (c) 270
  39. 39.Best estimate of 34 × 36? (a) 1200 (b) 120 (c) 12000
  40. 40.Best estimate of 47 × 16? (a) 100 (b) 1000 (c) 10000

Answer key

  1. 1400
  2. 6000
  3. 900
  4. 900
  5. 500
  6. 400
  7. 5400
  8. 1800
  9. 800
  10. 3600
  11. 500
  12. 1600
  13. 1500
  14. 4900
  15. 1100
  16. 2800
  17. 900
  18. 600
  19. 1000
  20. 1600
  21. 1600
  22. 800
  23. 5400
  24. 700
  25. 1000
  26. 300
  27. 800
  28. 1300
  29. 3200
  30. 5400
  31. 1400
  32. 1800
  33. 2000
  34. 1000
  35. 2400
  36. 400
  37. 800
  38. 2700
  39. 1200
  40. 1000

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