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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 452 · 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 480 + 292? (a) 1000 (b) 800 (c) 600
  2. 2.Best estimate of 26 × 96? (a) 300 (b) 3000 (c) 30000
  3. 3.Best estimate of 94 × 29? (a) 270 (b) 27000 (c) 2700
  4. 4.Best estimate of 56 × 46? (a) 300 (b) 30000 (c) 3000
  5. 5.Best estimate of 76 × 42? (a) 32000 (b) 3200 (c) 320
  6. 6.Best estimate of 92 × 33? (a) 2700 (b) 27000 (c) 270
  7. 7.Best estimate of 258 + 351? (a) 900 (b) 700 (c) 500
  8. 8.Best estimate of 436 + 361? (a) 800 (b) 600 (c) 1000
  9. 9.Best estimate of 558 + 270? (a) 1100 (b) 900 (c) 700
  10. 10.Best estimate of 405 + 248? (a) 600 (b) 800 (c) 400
  11. 11.Best estimate of 72 × 96? (a) 700 (b) 7000 (c) 70000
  12. 12.Best estimate of 142 + 281? (a) 200 (b) 600 (c) 400
  13. 13.Best estimate of 30 × 92? (a) 2700 (b) 27000 (c) 270
  14. 14.Best estimate of 51 × 36? (a) 20000 (b) 2000 (c) 200
  15. 15.Best estimate of 308 + 148? (a) 400 (b) 200 (c) 600
  16. 16.Best estimate of 491 + 613? (a) 1300 (b) 900 (c) 1100
  17. 17.Best estimate of 735 + 364? (a) 1300 (b) 1100 (c) 900
  18. 18.Best estimate of 447 + 607? (a) 800 (b) 1000 (c) 1200
  19. 19.Best estimate of 32 × 33? (a) 900 (b) 90 (c) 9000
  20. 20.Best estimate of 69 × 33? (a) 21000 (b) 2100 (c) 210
  21. 21.Best estimate of 764 + 466? (a) 1500 (b) 1100 (c) 1300
  22. 22.Best estimate of 680 + 298? (a) 1000 (b) 1200 (c) 800
  23. 23.Best estimate of 74 × 70? (a) 49000 (b) 4900 (c) 490
  24. 24.Best estimate of 721 + 613? (a) 1300 (b) 1100 (c) 1500
  25. 25.Best estimate of 461 + 808? (a) 1300 (b) 1100 (c) 1500
  26. 26.Best estimate of 122 + 187? (a) 100 (b) 300 (c) 500
  27. 27.Best estimate of 34 × 19? (a) 600 (b) 60 (c) 6000
  28. 28.Best estimate of 57 × 57? (a) 360 (b) 3600 (c) 36000
  29. 29.Best estimate of 391 + 557? (a) 1000 (b) 800 (c) 1200
  30. 30.Best estimate of 88 × 64? (a) 54000 (b) 540 (c) 5400
  31. 31.Best estimate of 196 + 864? (a) 900 (b) 1100 (c) 1300
  32. 32.Best estimate of 32 × 16? (a) 60 (b) 600 (c) 6000
  33. 33.Best estimate of 681 + 771? (a) 1500 (b) 1300 (c) 1700
  34. 34.Best estimate of 39 × 26? (a) 1200 (b) 12000 (c) 120
  35. 35.Best estimate of 309 + 657? (a) 800 (b) 1200 (c) 1000
  36. 36.Best estimate of 70 × 80? (a) 5600 (b) 560 (c) 56000
  37. 37.Best estimate of 170 + 125? (a) 300 (b) 500 (c) 100
  38. 38.Best estimate of 751 + 681? (a) 1300 (b) 1700 (c) 1500
  39. 39.Best estimate of 43 × 76? (a) 3200 (b) 320 (c) 32000
  40. 40.Best estimate of 616 + 214? (a) 800 (b) 600 (c) 1000

Answer key

  1. 800
  2. 3000
  3. 2700
  4. 3000
  5. 3200
  6. 2700
  7. 700
  8. 800
  9. 900
  10. 600
  11. 7000
  12. 400
  13. 2700
  14. 2000
  15. 400
  16. 1100
  17. 1100
  18. 1000
  19. 900
  20. 2100
  21. 1300
  22. 1000
  23. 4900
  24. 1300
  25. 1300
  26. 300
  27. 600
  28. 3600
  29. 1000
  30. 5400
  31. 1100
  32. 600
  33. 1500
  34. 1200
  35. 1000
  36. 5600
  37. 300
  38. 1500
  39. 3200
  40. 800

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