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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 699 · 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 649 + 212? (a) 600 (b) 800 (c) 1000
  2. 2.Best estimate of 62 × 98? (a) 60000 (b) 600 (c) 6000
  3. 3.Best estimate of 334 + 766? (a) 1300 (b) 900 (c) 1100
  4. 4.Best estimate of 753 + 286? (a) 1300 (b) 900 (c) 1100
  5. 5.Best estimate of 762 + 632? (a) 1400 (b) 1200 (c) 1600
  6. 6.Best estimate of 22 × 50? (a) 10000 (b) 100 (c) 1000
  7. 7.Best estimate of 208 + 386? (a) 600 (b) 400 (c) 800
  8. 8.Best estimate of 91 × 23? (a) 180 (b) 1800 (c) 18000
  9. 9.Best estimate of 44 × 27? (a) 12000 (b) 120 (c) 1200
  10. 10.Best estimate of 605 + 617? (a) 1400 (b) 1000 (c) 1200
  11. 11.Best estimate of 353 + 511? (a) 700 (b) 900 (c) 1100
  12. 12.Best estimate of 34 × 62? (a) 180 (b) 1800 (c) 18000
  13. 13.Best estimate of 26 × 60? (a) 180 (b) 1800 (c) 18000
  14. 14.Best estimate of 66 × 27? (a) 2100 (b) 21000 (c) 210
  15. 15.Best estimate of 419 + 737? (a) 900 (b) 1100 (c) 1300
  16. 16.Best estimate of 527 + 561? (a) 900 (b) 1100 (c) 1300
  17. 17.Best estimate of 495 + 222? (a) 700 (b) 500 (c) 900
  18. 18.Best estimate of 288 + 609? (a) 700 (b) 900 (c) 1100
  19. 19.Best estimate of 491 + 511? (a) 1200 (b) 1000 (c) 800
  20. 20.Best estimate of 90 × 53? (a) 45000 (b) 4500 (c) 450
  21. 21.Best estimate of 24 × 57? (a) 1200 (b) 120 (c) 12000
  22. 22.Best estimate of 54 × 12? (a) 50 (b) 500 (c) 5000
  23. 23.Best estimate of 193 + 434? (a) 600 (b) 800 (c) 400
  24. 24.Best estimate of 519 + 820? (a) 1300 (b) 1500 (c) 1100
  25. 25.Best estimate of 776 + 498? (a) 1500 (b) 1300 (c) 1100
  26. 26.Best estimate of 364 + 859? (a) 1500 (b) 1300 (c) 1100
  27. 27.Best estimate of 24 × 98? (a) 200 (b) 20000 (c) 2000
  28. 28.Best estimate of 40 × 12? (a) 4000 (b) 400 (c) 40
  29. 29.Best estimate of 334 + 132? (a) 400 (b) 600 (c) 200
  30. 30.Best estimate of 90 × 68? (a) 63000 (b) 630 (c) 6300
  31. 31.Best estimate of 68 × 51? (a) 3500 (b) 35000 (c) 350
  32. 32.Best estimate of 468 + 447? (a) 900 (b) 1100 (c) 700
  33. 33.Best estimate of 17 × 30? (a) 60 (b) 600 (c) 6000
  34. 34.Best estimate of 381 + 765? (a) 1400 (b) 1200 (c) 1000
  35. 35.Best estimate of 34 × 79? (a) 240 (b) 2400 (c) 24000
  36. 36.Best estimate of 744 + 810? (a) 1300 (b) 1500 (c) 1700
  37. 37.Best estimate of 13 × 87? (a) 9000 (b) 900 (c) 90
  38. 38.Best estimate of 770 + 248? (a) 1200 (b) 800 (c) 1000
  39. 39.Best estimate of 32 × 58? (a) 18000 (b) 180 (c) 1800
  40. 40.Best estimate of 815 + 854? (a) 1500 (b) 1700 (c) 1900

Answer key

  1. 800
  2. 6000
  3. 1100
  4. 1100
  5. 1400
  6. 1000
  7. 600
  8. 1800
  9. 1200
  10. 1200
  11. 900
  12. 1800
  13. 1800
  14. 2100
  15. 1100
  16. 1100
  17. 700
  18. 900
  19. 1000
  20. 4500
  21. 1200
  22. 500
  23. 600
  24. 1300
  25. 1300
  26. 1300
  27. 2000
  28. 400
  29. 400
  30. 6300
  31. 3500
  32. 900
  33. 600
  34. 1200
  35. 2400
  36. 1500
  37. 900
  38. 1000
  39. 1800
  40. 1700

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