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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 990 · 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 813 + 519? (a) 1500 (b) 1100 (c) 1300
  2. 2.Best estimate of 284 + 199? (a) 500 (b) 700 (c) 300
  3. 3.Best estimate of 59 × 92? (a) 5400 (b) 540 (c) 54000
  4. 4.Best estimate of 91 × 13? (a) 9000 (b) 90 (c) 900
  5. 5.Best estimate of 336 + 779? (a) 1100 (b) 1300 (c) 900
  6. 6.Best estimate of 687 + 702? (a) 1600 (b) 1200 (c) 1400
  7. 7.Best estimate of 81 × 64? (a) 48000 (b) 4800 (c) 480
  8. 8.Best estimate of 280 + 505? (a) 600 (b) 1000 (c) 800
  9. 9.Best estimate of 63 × 94? (a) 540 (b) 5400 (c) 54000
  10. 10.Best estimate of 32 × 92? (a) 270 (b) 27000 (c) 2700
  11. 11.Best estimate of 24 × 16? (a) 400 (b) 4000 (c) 40
  12. 12.Best estimate of 16 × 16? (a) 40 (b) 4000 (c) 400
  13. 13.Best estimate of 371 + 878? (a) 1300 (b) 1500 (c) 1100
  14. 14.Best estimate of 29 × 97? (a) 3000 (b) 300 (c) 30000
  15. 15.Best estimate of 54 × 46? (a) 2500 (b) 25000 (c) 250
  16. 16.Best estimate of 28 × 86? (a) 27000 (b) 2700 (c) 270
  17. 17.Best estimate of 26 × 36? (a) 12000 (b) 1200 (c) 120
  18. 18.Best estimate of 312 + 856? (a) 1400 (b) 1200 (c) 1000
  19. 19.Best estimate of 151 + 123? (a) 500 (b) 300 (c) 100
  20. 20.Best estimate of 749 + 466? (a) 1000 (b) 1200 (c) 1400
  21. 21.Best estimate of 443 + 878? (a) 1300 (b) 1100 (c) 1500
  22. 22.Best estimate of 62 × 54? (a) 3000 (b) 30000 (c) 300
  23. 23.Best estimate of 621 + 300? (a) 700 (b) 1100 (c) 900
  24. 24.Best estimate of 20 × 68? (a) 14000 (b) 140 (c) 1400
  25. 25.Best estimate of 361 + 338? (a) 500 (b) 900 (c) 700
  26. 26.Best estimate of 194 + 801? (a) 1000 (b) 800 (c) 1200
  27. 27.Best estimate of 86 × 18? (a) 180 (b) 18000 (c) 1800
  28. 28.Best estimate of 74 × 17? (a) 14000 (b) 140 (c) 1400
  29. 29.Best estimate of 339 + 231? (a) 300 (b) 500 (c) 700
  30. 30.Best estimate of 346 + 342? (a) 600 (b) 800 (c) 400
  31. 31.Best estimate of 130 + 773? (a) 1100 (b) 700 (c) 900
  32. 32.Best estimate of 94 × 20? (a) 180 (b) 18000 (c) 1800
  33. 33.Best estimate of 56 × 59? (a) 36000 (b) 3600 (c) 360
  34. 34.Best estimate of 64 × 43? (a) 240 (b) 24000 (c) 2400
  35. 35.Best estimate of 586 + 820? (a) 1200 (b) 1400 (c) 1600
  36. 36.Best estimate of 777 + 543? (a) 1300 (b) 1100 (c) 1500
  37. 37.Best estimate of 396 + 509? (a) 1100 (b) 700 (c) 900
  38. 38.Best estimate of 71 × 23? (a) 140 (b) 1400 (c) 14000
  39. 39.Best estimate of 780 + 805? (a) 1600 (b) 1800 (c) 1400
  40. 40.Best estimate of 544 + 259? (a) 1000 (b) 800 (c) 600

Answer key

  1. 1300
  2. 500
  3. 5400
  4. 900
  5. 1100
  6. 1400
  7. 4800
  8. 800
  9. 5400
  10. 2700
  11. 400
  12. 400
  13. 1300
  14. 3000
  15. 2500
  16. 2700
  17. 1200
  18. 1200
  19. 300
  20. 1200
  21. 1300
  22. 3000
  23. 900
  24. 1400
  25. 700
  26. 1000
  27. 1800
  28. 1400
  29. 500
  30. 600
  31. 900
  32. 1800
  33. 3600
  34. 2400
  35. 1400
  36. 1300
  37. 900
  38. 1400
  39. 1600
  40. 800

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