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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 993 · 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 76 × 74? (a) 560 (b) 5600 (c) 56000
  2. 2.Best estimate of 91 × 62? (a) 540 (b) 5400 (c) 54000
  3. 3.Best estimate of 76 × 39? (a) 32000 (b) 320 (c) 3200
  4. 4.Best estimate of 747 + 864? (a) 1800 (b) 1400 (c) 1600
  5. 5.Best estimate of 585 + 790? (a) 1400 (b) 1600 (c) 1200
  6. 6.Best estimate of 67 × 49? (a) 350 (b) 35000 (c) 3500
  7. 7.Best estimate of 64 × 44? (a) 240 (b) 2400 (c) 24000
  8. 8.Best estimate of 43 × 46? (a) 20000 (b) 200 (c) 2000
  9. 9.Best estimate of 72 × 58? (a) 4200 (b) 42000 (c) 420
  10. 10.Best estimate of 267 + 475? (a) 600 (b) 1000 (c) 800
  11. 11.Best estimate of 71 × 22? (a) 1400 (b) 14000 (c) 140
  12. 12.Best estimate of 80 × 23? (a) 160 (b) 16000 (c) 1600
  13. 13.Best estimate of 545 + 630? (a) 1100 (b) 900 (c) 1300
  14. 14.Best estimate of 79 × 33? (a) 240 (b) 2400 (c) 24000
  15. 15.Best estimate of 16 × 53? (a) 1000 (b) 10000 (c) 100
  16. 16.Best estimate of 89 × 22? (a) 18000 (b) 180 (c) 1800
  17. 17.Best estimate of 836 + 879? (a) 1700 (b) 1900 (c) 1500
  18. 18.Best estimate of 374 + 205? (a) 600 (b) 800 (c) 400
  19. 19.Best estimate of 16 × 79? (a) 16000 (b) 1600 (c) 160
  20. 20.Best estimate of 677 + 765? (a) 1700 (b) 1500 (c) 1300
  21. 21.Best estimate of 29 × 62? (a) 18000 (b) 180 (c) 1800
  22. 22.Best estimate of 594 + 336? (a) 900 (b) 700 (c) 1100
  23. 23.Best estimate of 70 × 12? (a) 7000 (b) 700 (c) 70
  24. 24.Best estimate of 24 × 18? (a) 40 (b) 400 (c) 4000
  25. 25.Best estimate of 785 + 135? (a) 700 (b) 1100 (c) 900
  26. 26.Best estimate of 145 + 844? (a) 700 (b) 900 (c) 1100
  27. 27.Best estimate of 89 × 60? (a) 540 (b) 54000 (c) 5400
  28. 28.Best estimate of 87 × 76? (a) 720 (b) 72000 (c) 7200
  29. 29.Best estimate of 582 + 213? (a) 1000 (b) 800 (c) 600
  30. 30.Best estimate of 79 × 27? (a) 24000 (b) 240 (c) 2400
  31. 31.Best estimate of 17 × 20? (a) 400 (b) 40 (c) 4000
  32. 32.Best estimate of 46 × 72? (a) 350 (b) 3500 (c) 35000
  33. 33.Best estimate of 41 × 93? (a) 360 (b) 3600 (c) 36000
  34. 34.Best estimate of 414 + 483? (a) 700 (b) 900 (c) 1100
  35. 35.Best estimate of 80 × 56? (a) 480 (b) 48000 (c) 4800
  36. 36.Best estimate of 63 × 14? (a) 60 (b) 600 (c) 6000
  37. 37.Best estimate of 403 + 864? (a) 1500 (b) 1300 (c) 1100
  38. 38.Best estimate of 270 + 346? (a) 600 (b) 400 (c) 800
  39. 39.Best estimate of 143 + 376? (a) 500 (b) 700 (c) 300
  40. 40.Best estimate of 322 + 595? (a) 900 (b) 1100 (c) 700

Answer key

  1. 5600
  2. 5400
  3. 3200
  4. 1600
  5. 1400
  6. 3500
  7. 2400
  8. 2000
  9. 4200
  10. 800
  11. 1400
  12. 1600
  13. 1100
  14. 2400
  15. 1000
  16. 1800
  17. 1700
  18. 600
  19. 1600
  20. 1500
  21. 1800
  22. 900
  23. 700
  24. 400
  25. 900
  26. 900
  27. 5400
  28. 7200
  29. 800
  30. 2400
  31. 400
  32. 3500
  33. 3600
  34. 900
  35. 4800
  36. 600
  37. 1300
  38. 600
  39. 500
  40. 900

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