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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 702 · 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 13 × 66? (a) 7000 (b) 70 (c) 700
  2. 2.Best estimate of 29 × 46? (a) 150 (b) 1500 (c) 15000
  3. 3.Best estimate of 70 × 66? (a) 49000 (b) 4900 (c) 490
  4. 4.Best estimate of 806 + 212? (a) 1000 (b) 1200 (c) 800
  5. 5.Best estimate of 94 × 56? (a) 540 (b) 54000 (c) 5400
  6. 6.Best estimate of 56 × 13? (a) 60 (b) 6000 (c) 600
  7. 7.Best estimate of 312 + 417? (a) 500 (b) 700 (c) 900
  8. 8.Best estimate of 298 + 643? (a) 1100 (b) 900 (c) 700
  9. 9.Best estimate of 96 × 49? (a) 500 (b) 5000 (c) 50000
  10. 10.Best estimate of 874 + 810? (a) 1700 (b) 1500 (c) 1900
  11. 11.Best estimate of 59 × 16? (a) 1200 (b) 120 (c) 12000
  12. 12.Best estimate of 27 × 88? (a) 27000 (b) 270 (c) 2700
  13. 13.Best estimate of 81 × 93? (a) 720 (b) 72000 (c) 7200
  14. 14.Best estimate of 77 × 83? (a) 640 (b) 6400 (c) 64000
  15. 15.Best estimate of 66 × 38? (a) 280 (b) 28000 (c) 2800
  16. 16.Best estimate of 875 + 716? (a) 1800 (b) 1600 (c) 1400
  17. 17.Best estimate of 34 × 59? (a) 1800 (b) 18000 (c) 180
  18. 18.Best estimate of 36 × 20? (a) 80 (b) 800 (c) 8000
  19. 19.Best estimate of 306 + 490? (a) 800 (b) 600 (c) 1000
  20. 20.Best estimate of 47 × 49? (a) 250 (b) 2500 (c) 25000
  21. 21.Best estimate of 59 × 94? (a) 540 (b) 54000 (c) 5400
  22. 22.Best estimate of 481 + 711? (a) 1200 (b) 1400 (c) 1000
  23. 23.Best estimate of 82 × 68? (a) 56000 (b) 5600 (c) 560
  24. 24.Best estimate of 53 × 17? (a) 10000 (b) 100 (c) 1000
  25. 25.Best estimate of 61 × 66? (a) 4200 (b) 42000 (c) 420
  26. 26.Best estimate of 324 + 208? (a) 700 (b) 500 (c) 300
  27. 27.Best estimate of 642 + 374? (a) 1000 (b) 800 (c) 1200
  28. 28.Best estimate of 51 × 36? (a) 20000 (b) 2000 (c) 200
  29. 29.Best estimate of 31 × 37? (a) 1200 (b) 12000 (c) 120
  30. 30.Best estimate of 48 × 59? (a) 3000 (b) 300 (c) 30000
  31. 31.Best estimate of 41 × 42? (a) 160 (b) 1600 (c) 16000
  32. 32.Best estimate of 305 + 603? (a) 700 (b) 1100 (c) 900
  33. 33.Best estimate of 70 × 64? (a) 4200 (b) 42000 (c) 420
  34. 34.Best estimate of 48 × 42? (a) 200 (b) 20000 (c) 2000
  35. 35.Best estimate of 748 + 511? (a) 1400 (b) 1200 (c) 1000
  36. 36.Best estimate of 732 + 594? (a) 1300 (b) 1500 (c) 1100
  37. 37.Best estimate of 16 × 31? (a) 600 (b) 6000 (c) 60
  38. 38.Best estimate of 224 + 158? (a) 200 (b) 600 (c) 400
  39. 39.Best estimate of 248 + 309? (a) 500 (b) 700 (c) 300
  40. 40.Best estimate of 69 × 34? (a) 210 (b) 2100 (c) 21000

Answer key

  1. 700
  2. 1500
  3. 4900
  4. 1000
  5. 5400
  6. 600
  7. 700
  8. 900
  9. 5000
  10. 1700
  11. 1200
  12. 2700
  13. 7200
  14. 6400
  15. 2800
  16. 1600
  17. 1800
  18. 800
  19. 800
  20. 2500
  21. 5400
  22. 1200
  23. 5600
  24. 1000
  25. 4200
  26. 500
  27. 1000
  28. 2000
  29. 1200
  30. 3000
  31. 1600
  32. 900
  33. 4200
  34. 2000
  35. 1200
  36. 1300
  37. 600
  38. 400
  39. 500
  40. 2100

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