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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 785 · 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 26 × 96? (a) 30000 (b) 3000 (c) 300
  2. 2.Best estimate of 588 + 353? (a) 800 (b) 1000 (c) 1200
  3. 3.Best estimate of 60 × 16? (a) 1200 (b) 12000 (c) 120
  4. 4.Best estimate of 82 × 66? (a) 5600 (b) 56000 (c) 560
  5. 5.Best estimate of 291 + 785? (a) 1300 (b) 900 (c) 1100
  6. 6.Best estimate of 843 + 661? (a) 1300 (b) 1700 (c) 1500
  7. 7.Best estimate of 28 × 36? (a) 12000 (b) 120 (c) 1200
  8. 8.Best estimate of 695 + 638? (a) 1500 (b) 1100 (c) 1300
  9. 9.Best estimate of 79 × 32? (a) 24000 (b) 2400 (c) 240
  10. 10.Best estimate of 303 + 141? (a) 600 (b) 200 (c) 400
  11. 11.Best estimate of 42 × 98? (a) 400 (b) 4000 (c) 40000
  12. 12.Best estimate of 82 × 71? (a) 5600 (b) 56000 (c) 560
  13. 13.Best estimate of 76 × 77? (a) 6400 (b) 64000 (c) 640
  14. 14.Best estimate of 17 × 42? (a) 80 (b) 800 (c) 8000
  15. 15.Best estimate of 72 × 19? (a) 140 (b) 14000 (c) 1400
  16. 16.Best estimate of 403 + 320? (a) 500 (b) 900 (c) 700
  17. 17.Best estimate of 214 + 800? (a) 1000 (b) 1200 (c) 800
  18. 18.Best estimate of 627 + 343? (a) 1100 (b) 700 (c) 900
  19. 19.Best estimate of 14 × 96? (a) 100 (b) 10000 (c) 1000
  20. 20.Best estimate of 31 × 46? (a) 150 (b) 15000 (c) 1500
  21. 21.Best estimate of 46 × 84? (a) 400 (b) 4000 (c) 40000
  22. 22.Best estimate of 26 × 28? (a) 900 (b) 90 (c) 9000
  23. 23.Best estimate of 77 × 44? (a) 320 (b) 32000 (c) 3200
  24. 24.Best estimate of 622 + 794? (a) 1600 (b) 1400 (c) 1200
  25. 25.Best estimate of 514 + 600? (a) 1100 (b) 1300 (c) 900
  26. 26.Best estimate of 91 × 78? (a) 720 (b) 7200 (c) 72000
  27. 27.Best estimate of 763 + 173? (a) 1000 (b) 800 (c) 1200
  28. 28.Best estimate of 588 + 351? (a) 1200 (b) 800 (c) 1000
  29. 29.Best estimate of 610 + 861? (a) 1700 (b) 1300 (c) 1500
  30. 30.Best estimate of 555 + 689? (a) 1300 (b) 1500 (c) 1100
  31. 31.Best estimate of 869 + 336? (a) 1200 (b) 1000 (c) 1400
  32. 32.Best estimate of 88 × 36? (a) 3600 (b) 360 (c) 36000
  33. 33.Best estimate of 46 × 46? (a) 250 (b) 25000 (c) 2500
  34. 34.Best estimate of 17 × 70? (a) 14000 (b) 1400 (c) 140
  35. 35.Best estimate of 18 × 86? (a) 18000 (b) 1800 (c) 180
  36. 36.Best estimate of 242 + 653? (a) 1100 (b) 700 (c) 900
  37. 37.Best estimate of 81 × 16? (a) 1600 (b) 160 (c) 16000
  38. 38.Best estimate of 353 + 386? (a) 800 (b) 600 (c) 1000
  39. 39.Best estimate of 96 × 51? (a) 5000 (b) 50000 (c) 500
  40. 40.Best estimate of 386 + 143? (a) 300 (b) 700 (c) 500

Answer key

  1. 3000
  2. 1000
  3. 1200
  4. 5600
  5. 1100
  6. 1500
  7. 1200
  8. 1300
  9. 2400
  10. 400
  11. 4000
  12. 5600
  13. 6400
  14. 800
  15. 1400
  16. 700
  17. 1000
  18. 900
  19. 1000
  20. 1500
  21. 4000
  22. 900
  23. 3200
  24. 1400
  25. 1100
  26. 7200
  27. 1000
  28. 1000
  29. 1500
  30. 1300
  31. 1200
  32. 3600
  33. 2500
  34. 1400
  35. 1800
  36. 900
  37. 1600
  38. 800
  39. 5000
  40. 500

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