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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 462 · 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 72 × 62? (a) 4200 (b) 420 (c) 42000
  2. 2.Best estimate of 96 × 36? (a) 4000 (b) 40000 (c) 400
  3. 3.Best estimate of 435 + 699? (a) 1100 (b) 900 (c) 1300
  4. 4.Best estimate of 70 × 77? (a) 56000 (b) 5600 (c) 560
  5. 5.Best estimate of 702 + 141? (a) 800 (b) 1000 (c) 600
  6. 6.Best estimate of 378 + 164? (a) 800 (b) 600 (c) 400
  7. 7.Best estimate of 432 + 662? (a) 1100 (b) 1300 (c) 900
  8. 8.Best estimate of 873 + 261? (a) 1400 (b) 1200 (c) 1000
  9. 9.Best estimate of 264 + 527? (a) 600 (b) 800 (c) 1000
  10. 10.Best estimate of 79 × 88? (a) 72000 (b) 720 (c) 7200
  11. 11.Best estimate of 425 + 756? (a) 1400 (b) 1200 (c) 1000
  12. 12.Best estimate of 38 × 60? (a) 2400 (b) 240 (c) 24000
  13. 13.Best estimate of 722 + 503? (a) 1400 (b) 1200 (c) 1000
  14. 14.Best estimate of 37 × 36? (a) 16000 (b) 1600 (c) 160
  15. 15.Best estimate of 13 × 71? (a) 700 (b) 7000 (c) 70
  16. 16.Best estimate of 553 + 467? (a) 1100 (b) 1300 (c) 900
  17. 17.Best estimate of 411 + 231? (a) 800 (b) 600 (c) 400
  18. 18.Best estimate of 333 + 366? (a) 500 (b) 700 (c) 900
  19. 19.Best estimate of 252 + 632? (a) 900 (b) 700 (c) 1100
  20. 20.Best estimate of 28 × 19? (a) 600 (b) 60 (c) 6000
  21. 21.Best estimate of 70 × 44? (a) 28000 (b) 2800 (c) 280
  22. 22.Best estimate of 653 + 593? (a) 1100 (b) 1500 (c) 1300
  23. 23.Best estimate of 715 + 631? (a) 1100 (b) 1300 (c) 1500
  24. 24.Best estimate of 21 × 16? (a) 4000 (b) 400 (c) 40
  25. 25.Best estimate of 71 × 91? (a) 630 (b) 63000 (c) 6300
  26. 26.Best estimate of 236 + 341? (a) 500 (b) 300 (c) 700
  27. 27.Best estimate of 49 × 76? (a) 4000 (b) 40000 (c) 400
  28. 28.Best estimate of 62 × 57? (a) 36000 (b) 3600 (c) 360
  29. 29.Best estimate of 516 + 215? (a) 700 (b) 500 (c) 900
  30. 30.Best estimate of 47 × 60? (a) 3000 (b) 30000 (c) 300
  31. 31.Best estimate of 879 + 533? (a) 1400 (b) 1600 (c) 1200
  32. 32.Best estimate of 21 × 50? (a) 10000 (b) 1000 (c) 100
  33. 33.Best estimate of 661 + 857? (a) 1400 (b) 1600 (c) 1800
  34. 34.Best estimate of 680 + 804? (a) 1500 (b) 1700 (c) 1300
  35. 35.Best estimate of 90 × 49? (a) 45000 (b) 4500 (c) 450
  36. 36.Best estimate of 46 × 86? (a) 450 (b) 45000 (c) 4500
  37. 37.Best estimate of 80 × 56? (a) 48000 (b) 480 (c) 4800
  38. 38.Best estimate of 323 + 526? (a) 1000 (b) 800 (c) 600
  39. 39.Best estimate of 442 + 182? (a) 800 (b) 600 (c) 400
  40. 40.Best estimate of 255 + 760? (a) 900 (b) 1100 (c) 1300

Answer key

  1. 4200
  2. 4000
  3. 1100
  4. 5600
  5. 800
  6. 600
  7. 1100
  8. 1200
  9. 800
  10. 7200
  11. 1200
  12. 2400
  13. 1200
  14. 1600
  15. 700
  16. 1100
  17. 600
  18. 700
  19. 900
  20. 600
  21. 2800
  22. 1300
  23. 1300
  24. 400
  25. 6300
  26. 500
  27. 4000
  28. 3600
  29. 700
  30. 3000
  31. 1400
  32. 1000
  33. 1600
  34. 1500
  35. 4500
  36. 4500
  37. 4800
  38. 800
  39. 600
  40. 1100

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