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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 592 · 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 141 + 269? (a) 600 (b) 400 (c) 200
  2. 2.Best estimate of 327 + 562? (a) 1100 (b) 900 (c) 700
  3. 3.Best estimate of 858 + 860? (a) 1800 (b) 2000 (c) 1600
  4. 4.Best estimate of 26 × 21? (a) 600 (b) 6000 (c) 60
  5. 5.Best estimate of 94 × 19? (a) 1800 (b) 18000 (c) 180
  6. 6.Best estimate of 49 × 66? (a) 350 (b) 3500 (c) 35000
  7. 7.Best estimate of 446 + 220? (a) 800 (b) 400 (c) 600
  8. 8.Best estimate of 155 + 275? (a) 700 (b) 500 (c) 300
  9. 9.Best estimate of 212 + 701? (a) 1100 (b) 700 (c) 900
  10. 10.Best estimate of 83 × 54? (a) 400 (b) 4000 (c) 40000
  11. 11.Best estimate of 467 + 535? (a) 800 (b) 1000 (c) 1200
  12. 12.Best estimate of 76 × 49? (a) 400 (b) 40000 (c) 4000
  13. 13.Best estimate of 12 × 66? (a) 7000 (b) 70 (c) 700
  14. 14.Best estimate of 74 × 13? (a) 7000 (b) 700 (c) 70
  15. 15.Best estimate of 90 × 44? (a) 360 (b) 3600 (c) 36000
  16. 16.Best estimate of 16 × 31? (a) 60 (b) 6000 (c) 600
  17. 17.Best estimate of 425 + 865? (a) 1500 (b) 1100 (c) 1300
  18. 18.Best estimate of 49 × 32? (a) 150 (b) 15000 (c) 1500
  19. 19.Best estimate of 18 × 24? (a) 400 (b) 4000 (c) 40
  20. 20.Best estimate of 44 × 52? (a) 2000 (b) 200 (c) 20000
  21. 21.Best estimate of 20 × 68? (a) 1400 (b) 14000 (c) 140
  22. 22.Best estimate of 293 + 585? (a) 900 (b) 700 (c) 1100
  23. 23.Best estimate of 84 × 28? (a) 24000 (b) 2400 (c) 240
  24. 24.Best estimate of 335 + 504? (a) 600 (b) 1000 (c) 800
  25. 25.Best estimate of 62 × 47? (a) 300 (b) 30000 (c) 3000
  26. 26.Best estimate of 86 × 70? (a) 630 (b) 63000 (c) 6300
  27. 27.Best estimate of 33 × 96? (a) 3000 (b) 300 (c) 30000
  28. 28.Best estimate of 206 + 283? (a) 700 (b) 500 (c) 300
  29. 29.Best estimate of 586 + 172? (a) 800 (b) 1000 (c) 600
  30. 30.Best estimate of 16 × 67? (a) 14000 (b) 140 (c) 1400
  31. 31.Best estimate of 243 + 307? (a) 700 (b) 300 (c) 500
  32. 32.Best estimate of 19 × 54? (a) 1000 (b) 10000 (c) 100
  33. 33.Best estimate of 61 × 44? (a) 2400 (b) 240 (c) 24000
  34. 34.Best estimate of 545 + 147? (a) 400 (b) 600 (c) 800
  35. 35.Best estimate of 84 × 80? (a) 64000 (b) 6400 (c) 640
  36. 36.Best estimate of 59 × 88? (a) 540 (b) 54000 (c) 5400
  37. 37.Best estimate of 296 + 673? (a) 1200 (b) 800 (c) 1000
  38. 38.Best estimate of 97 × 86? (a) 9000 (b) 900 (c) 90000
  39. 39.Best estimate of 49 × 63? (a) 30000 (b) 3000 (c) 300
  40. 40.Best estimate of 87 × 76? (a) 7200 (b) 72000 (c) 720

Answer key

  1. 400
  2. 900
  3. 1800
  4. 600
  5. 1800
  6. 3500
  7. 600
  8. 500
  9. 900
  10. 4000
  11. 1000
  12. 4000
  13. 700
  14. 700
  15. 3600
  16. 600
  17. 1300
  18. 1500
  19. 400
  20. 2000
  21. 1400
  22. 900
  23. 2400
  24. 800
  25. 3000
  26. 6300
  27. 3000
  28. 500
  29. 800
  30. 1400
  31. 500
  32. 1000
  33. 2400
  34. 600
  35. 6400
  36. 5400
  37. 1000
  38. 9000
  39. 3000
  40. 7200

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