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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 392 · 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 482 + 877? (a) 1200 (b) 1400 (c) 1600
  2. 2.Best estimate of 49 × 63? (a) 3000 (b) 300 (c) 30000
  3. 3.Best estimate of 427 + 711? (a) 1300 (b) 1100 (c) 900
  4. 4.Best estimate of 231 + 414? (a) 600 (b) 800 (c) 400
  5. 5.Best estimate of 464 + 696? (a) 1400 (b) 1200 (c) 1000
  6. 6.Best estimate of 793 + 490? (a) 1100 (b) 1500 (c) 1300
  7. 7.Best estimate of 658 + 462? (a) 1200 (b) 1400 (c) 1000
  8. 8.Best estimate of 324 + 315? (a) 400 (b) 600 (c) 800
  9. 9.Best estimate of 291 + 448? (a) 900 (b) 500 (c) 700
  10. 10.Best estimate of 80 × 69? (a) 56000 (b) 5600 (c) 560
  11. 11.Best estimate of 549 + 286? (a) 800 (b) 600 (c) 1000
  12. 12.Best estimate of 592 + 175? (a) 1000 (b) 800 (c) 600
  13. 13.Best estimate of 43 × 77? (a) 32000 (b) 320 (c) 3200
  14. 14.Best estimate of 225 + 680? (a) 900 (b) 1100 (c) 700
  15. 15.Best estimate of 632 + 149? (a) 900 (b) 500 (c) 700
  16. 16.Best estimate of 608 + 160? (a) 800 (b) 1000 (c) 600
  17. 17.Best estimate of 661 + 709? (a) 1200 (b) 1600 (c) 1400
  18. 18.Best estimate of 96 × 46? (a) 50000 (b) 500 (c) 5000
  19. 19.Best estimate of 705 + 694? (a) 1400 (b) 1200 (c) 1600
  20. 20.Best estimate of 299 + 562? (a) 700 (b) 1100 (c) 900
  21. 21.Best estimate of 154 + 694? (a) 700 (b) 900 (c) 1100
  22. 22.Best estimate of 457 + 763? (a) 1500 (b) 1300 (c) 1100
  23. 23.Best estimate of 827 + 697? (a) 1300 (b) 1700 (c) 1500
  24. 24.Best estimate of 54 × 89? (a) 4500 (b) 450 (c) 45000
  25. 25.Best estimate of 249 + 687? (a) 900 (b) 700 (c) 1100
  26. 26.Best estimate of 82 × 94? (a) 7200 (b) 720 (c) 72000
  27. 27.Best estimate of 94 × 87? (a) 81000 (b) 8100 (c) 810
  28. 28.Best estimate of 241 + 252? (a) 500 (b) 700 (c) 300
  29. 29.Best estimate of 17 × 68? (a) 140 (b) 14000 (c) 1400
  30. 30.Best estimate of 332 + 467? (a) 800 (b) 1000 (c) 600
  31. 31.Best estimate of 448 + 746? (a) 1100 (b) 1300 (c) 900
  32. 32.Best estimate of 41 × 22? (a) 800 (b) 8000 (c) 80
  33. 33.Best estimate of 46 × 16? (a) 1000 (b) 10000 (c) 100
  34. 34.Best estimate of 70 × 60? (a) 4200 (b) 420 (c) 42000
  35. 35.Best estimate of 59 × 39? (a) 24000 (b) 2400 (c) 240
  36. 36.Best estimate of 70 × 21? (a) 1400 (b) 14000 (c) 140
  37. 37.Best estimate of 91 × 66? (a) 6300 (b) 63000 (c) 630
  38. 38.Best estimate of 41 × 48? (a) 200 (b) 2000 (c) 20000
  39. 39.Best estimate of 373 + 305? (a) 900 (b) 700 (c) 500
  40. 40.Best estimate of 91 × 29? (a) 2700 (b) 270 (c) 27000

Answer key

  1. 1400
  2. 3000
  3. 1100
  4. 600
  5. 1200
  6. 1300
  7. 1200
  8. 600
  9. 700
  10. 5600
  11. 800
  12. 800
  13. 3200
  14. 900
  15. 700
  16. 800
  17. 1400
  18. 5000
  19. 1400
  20. 900
  21. 900
  22. 1300
  23. 1500
  24. 4500
  25. 900
  26. 7200
  27. 8100
  28. 500
  29. 1400
  30. 800
  31. 1100
  32. 800
  33. 1000
  34. 4200
  35. 2400
  36. 1400
  37. 6300
  38. 2000
  39. 700
  40. 2700

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