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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 236 · 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 256 + 295? (a) 600 (b) 800 (c) 400
  2. 2.Best estimate of 91 × 26? (a) 2700 (b) 27000 (c) 270
  3. 3.Best estimate of 136 + 186? (a) 100 (b) 300 (c) 500
  4. 4.Best estimate of 49 × 44? (a) 2000 (b) 200 (c) 20000
  5. 5.Best estimate of 872 + 353? (a) 1300 (b) 1500 (c) 1100
  6. 6.Best estimate of 20 × 81? (a) 160 (b) 16000 (c) 1600
  7. 7.Best estimate of 23 × 48? (a) 10000 (b) 100 (c) 1000
  8. 8.Best estimate of 463 + 520? (a) 1000 (b) 800 (c) 1200
  9. 9.Best estimate of 26 × 96? (a) 3000 (b) 300 (c) 30000
  10. 10.Best estimate of 729 + 132? (a) 600 (b) 800 (c) 1000
  11. 11.Best estimate of 34 × 51? (a) 1500 (b) 15000 (c) 150
  12. 12.Best estimate of 56 × 73? (a) 420 (b) 4200 (c) 42000
  13. 13.Best estimate of 92 × 30? (a) 2700 (b) 27000 (c) 270
  14. 14.Best estimate of 86 × 28? (a) 2700 (b) 27000 (c) 270
  15. 15.Best estimate of 339 + 841? (a) 1100 (b) 900 (c) 1300
  16. 16.Best estimate of 202 + 291? (a) 300 (b) 700 (c) 500
  17. 17.Best estimate of 867 + 349? (a) 1400 (b) 1200 (c) 1000
  18. 18.Best estimate of 729 + 746? (a) 1400 (b) 1600 (c) 1200
  19. 19.Best estimate of 703 + 295? (a) 1000 (b) 800 (c) 1200
  20. 20.Best estimate of 848 + 489? (a) 1500 (b) 1300 (c) 1100
  21. 21.Best estimate of 547 + 356? (a) 900 (b) 700 (c) 1100
  22. 22.Best estimate of 16 × 40? (a) 80 (b) 8000 (c) 800
  23. 23.Best estimate of 720 + 721? (a) 1400 (b) 1200 (c) 1600
  24. 24.Best estimate of 595 + 348? (a) 1100 (b) 700 (c) 900
  25. 25.Best estimate of 831 + 531? (a) 1100 (b) 1500 (c) 1300
  26. 26.Best estimate of 714 + 357? (a) 1300 (b) 1100 (c) 900
  27. 27.Best estimate of 66 × 96? (a) 70000 (b) 700 (c) 7000
  28. 28.Best estimate of 32 × 41? (a) 1200 (b) 12000 (c) 120
  29. 29.Best estimate of 790 + 622? (a) 1200 (b) 1600 (c) 1400
  30. 30.Best estimate of 26 × 88? (a) 27000 (b) 270 (c) 2700
  31. 31.Best estimate of 82 × 22? (a) 16000 (b) 160 (c) 1600
  32. 32.Best estimate of 83 × 36? (a) 3200 (b) 32000 (c) 320
  33. 33.Best estimate of 94 × 23? (a) 18000 (b) 180 (c) 1800
  34. 34.Best estimate of 83 × 18? (a) 160 (b) 1600 (c) 16000
  35. 35.Best estimate of 34 × 23? (a) 6000 (b) 60 (c) 600
  36. 36.Best estimate of 97 × 93? (a) 9000 (b) 90000 (c) 900
  37. 37.Best estimate of 347 + 654? (a) 800 (b) 1000 (c) 1200
  38. 38.Best estimate of 576 + 420? (a) 1200 (b) 800 (c) 1000
  39. 39.Best estimate of 87 × 66? (a) 630 (b) 6300 (c) 63000
  40. 40.Best estimate of 56 × 94? (a) 5400 (b) 54000 (c) 540

Answer key

  1. 600
  2. 2700
  3. 300
  4. 2000
  5. 1300
  6. 1600
  7. 1000
  8. 1000
  9. 3000
  10. 800
  11. 1500
  12. 4200
  13. 2700
  14. 2700
  15. 1100
  16. 500
  17. 1200
  18. 1400
  19. 1000
  20. 1300
  21. 900
  22. 800
  23. 1400
  24. 900
  25. 1300
  26. 1100
  27. 7000
  28. 1200
  29. 1400
  30. 2700
  31. 1600
  32. 3200
  33. 1800
  34. 1600
  35. 600
  36. 9000
  37. 1000
  38. 1000
  39. 6300
  40. 5400

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