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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 864 · 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 319 + 308? (a) 800 (b) 400 (c) 600
  2. 2.Best estimate of 61 × 44? (a) 240 (b) 24000 (c) 2400
  3. 3.Best estimate of 608 + 253? (a) 700 (b) 900 (c) 1100
  4. 4.Best estimate of 390 + 222? (a) 800 (b) 400 (c) 600
  5. 5.Best estimate of 692 + 161? (a) 700 (b) 1100 (c) 900
  6. 6.Best estimate of 93 × 62? (a) 54000 (b) 540 (c) 5400
  7. 7.Best estimate of 28 × 90? (a) 27000 (b) 270 (c) 2700
  8. 8.Best estimate of 22 × 49? (a) 100 (b) 10000 (c) 1000
  9. 9.Best estimate of 79 × 54? (a) 40000 (b) 400 (c) 4000
  10. 10.Best estimate of 28 × 98? (a) 3000 (b) 30000 (c) 300
  11. 11.Best estimate of 13 × 13? (a) 10 (b) 1000 (c) 100
  12. 12.Best estimate of 637 + 381? (a) 800 (b) 1200 (c) 1000
  13. 13.Best estimate of 851 + 796? (a) 1700 (b) 1500 (c) 1900
  14. 14.Best estimate of 12 × 22? (a) 200 (b) 2000 (c) 20
  15. 15.Best estimate of 159 + 399? (a) 800 (b) 400 (c) 600
  16. 16.Best estimate of 382 + 479? (a) 700 (b) 1100 (c) 900
  17. 17.Best estimate of 16 × 96? (a) 20000 (b) 2000 (c) 200
  18. 18.Best estimate of 72 × 76? (a) 560 (b) 56000 (c) 5600
  19. 19.Best estimate of 547 + 221? (a) 500 (b) 700 (c) 900
  20. 20.Best estimate of 17 × 61? (a) 12000 (b) 1200 (c) 120
  21. 21.Best estimate of 18 × 32? (a) 6000 (b) 600 (c) 60
  22. 22.Best estimate of 91 × 79? (a) 72000 (b) 7200 (c) 720
  23. 23.Best estimate of 98 × 98? (a) 100000 (b) 1000 (c) 10000
  24. 24.Best estimate of 828 + 403? (a) 1200 (b) 1000 (c) 1400
  25. 25.Best estimate of 839 + 362? (a) 1000 (b) 1200 (c) 1400
  26. 26.Best estimate of 48 × 88? (a) 450 (b) 4500 (c) 45000
  27. 27.Best estimate of 12 × 77? (a) 8000 (b) 800 (c) 80
  28. 28.Best estimate of 482 + 377? (a) 900 (b) 700 (c) 1100
  29. 29.Best estimate of 47 × 61? (a) 3000 (b) 30000 (c) 300
  30. 30.Best estimate of 86 × 66? (a) 6300 (b) 630 (c) 63000
  31. 31.Best estimate of 52 × 46? (a) 2500 (b) 250 (c) 25000
  32. 32.Best estimate of 483 + 354? (a) 1100 (b) 700 (c) 900
  33. 33.Best estimate of 96 × 37? (a) 4000 (b) 400 (c) 40000
  34. 34.Best estimate of 838 + 807? (a) 1800 (b) 1400 (c) 1600
  35. 35.Best estimate of 62 × 59? (a) 360 (b) 3600 (c) 36000
  36. 36.Best estimate of 72 × 90? (a) 6300 (b) 63000 (c) 630
  37. 37.Best estimate of 385 + 598? (a) 800 (b) 1000 (c) 1200
  38. 38.Best estimate of 541 + 540? (a) 800 (b) 1200 (c) 1000
  39. 39.Best estimate of 28 × 94? (a) 2700 (b) 27000 (c) 270
  40. 40.Best estimate of 24 × 62? (a) 1200 (b) 12000 (c) 120

Answer key

  1. 600
  2. 2400
  3. 900
  4. 600
  5. 900
  6. 5400
  7. 2700
  8. 1000
  9. 4000
  10. 3000
  11. 100
  12. 1000
  13. 1700
  14. 200
  15. 600
  16. 900
  17. 2000
  18. 5600
  19. 700
  20. 1200
  21. 600
  22. 7200
  23. 10000
  24. 1200
  25. 1200
  26. 4500
  27. 800
  28. 900
  29. 3000
  30. 6300
  31. 2500
  32. 900
  33. 4000
  34. 1600
  35. 3600
  36. 6300
  37. 1000
  38. 1000
  39. 2700
  40. 1200

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