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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 764 · 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 193 + 383? (a) 600 (b) 400 (c) 800
  2. 2.Best estimate of 34 × 76? (a) 2400 (b) 240 (c) 24000
  3. 3.Best estimate of 19 × 50? (a) 100 (b) 1000 (c) 10000
  4. 4.Best estimate of 851 + 818? (a) 1900 (b) 1700 (c) 1500
  5. 5.Best estimate of 653 + 691? (a) 1400 (b) 1600 (c) 1200
  6. 6.Best estimate of 633 + 128? (a) 700 (b) 500 (c) 900
  7. 7.Best estimate of 89 × 41? (a) 3600 (b) 36000 (c) 360
  8. 8.Best estimate of 16 × 19? (a) 400 (b) 40 (c) 4000
  9. 9.Best estimate of 267 + 551? (a) 1100 (b) 700 (c) 900
  10. 10.Best estimate of 16 × 37? (a) 8000 (b) 80 (c) 800
  11. 11.Best estimate of 515 + 516? (a) 1000 (b) 800 (c) 1200
  12. 12.Best estimate of 209 + 493? (a) 900 (b) 500 (c) 700
  13. 13.Best estimate of 80 × 31? (a) 240 (b) 24000 (c) 2400
  14. 14.Best estimate of 77 × 30? (a) 240 (b) 24000 (c) 2400
  15. 15.Best estimate of 97 × 49? (a) 50000 (b) 500 (c) 5000
  16. 16.Best estimate of 33 × 32? (a) 9000 (b) 900 (c) 90
  17. 17.Best estimate of 600 + 800? (a) 1200 (b) 1400 (c) 1600
  18. 18.Best estimate of 42 × 36? (a) 1600 (b) 16000 (c) 160
  19. 19.Best estimate of 410 + 581? (a) 800 (b) 1000 (c) 1200
  20. 20.Best estimate of 97 × 83? (a) 80000 (b) 800 (c) 8000
  21. 21.Best estimate of 14 × 76? (a) 800 (b) 8000 (c) 80
  22. 22.Best estimate of 770 + 445? (a) 1400 (b) 1200 (c) 1000
  23. 23.Best estimate of 97 × 34? (a) 30000 (b) 3000 (c) 300
  24. 24.Best estimate of 420 + 175? (a) 600 (b) 800 (c) 400
  25. 25.Best estimate of 76 × 72? (a) 5600 (b) 56000 (c) 560
  26. 26.Best estimate of 30 × 17? (a) 600 (b) 6000 (c) 60
  27. 27.Best estimate of 574 + 153? (a) 800 (b) 1000 (c) 600
  28. 28.Best estimate of 24 × 16? (a) 4000 (b) 400 (c) 40
  29. 29.Best estimate of 512 + 152? (a) 700 (b) 500 (c) 900
  30. 30.Best estimate of 766 + 474? (a) 1100 (b) 1300 (c) 1500
  31. 31.Best estimate of 63 × 77? (a) 480 (b) 4800 (c) 48000
  32. 32.Best estimate of 333 + 854? (a) 1000 (b) 1200 (c) 1400
  33. 33.Best estimate of 22 × 48? (a) 10000 (b) 100 (c) 1000
  34. 34.Best estimate of 54 × 56? (a) 3000 (b) 300 (c) 30000
  35. 35.Best estimate of 714 + 639? (a) 1300 (b) 1500 (c) 1100
  36. 36.Best estimate of 12 × 20? (a) 200 (b) 2000 (c) 20
  37. 37.Best estimate of 767 + 772? (a) 1800 (b) 1400 (c) 1600
  38. 38.Best estimate of 290 + 712? (a) 1000 (b) 1200 (c) 800
  39. 39.Best estimate of 538 + 608? (a) 1100 (b) 900 (c) 1300
  40. 40.Best estimate of 33 × 44? (a) 12000 (b) 120 (c) 1200

Answer key

  1. 600
  2. 2400
  3. 1000
  4. 1700
  5. 1400
  6. 700
  7. 3600
  8. 400
  9. 900
  10. 800
  11. 1000
  12. 700
  13. 2400
  14. 2400
  15. 5000
  16. 900
  17. 1400
  18. 1600
  19. 1000
  20. 8000
  21. 800
  22. 1200
  23. 3000
  24. 600
  25. 5600
  26. 600
  27. 800
  28. 400
  29. 700
  30. 1300
  31. 4800
  32. 1200
  33. 1000
  34. 3000
  35. 1300
  36. 200
  37. 1600
  38. 1000
  39. 1100
  40. 1200

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