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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 587 · 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 467 + 727? (a) 1400 (b) 1000 (c) 1200
  2. 2.Best estimate of 49 × 33? (a) 1500 (b) 15000 (c) 150
  3. 3.Best estimate of 68 × 72? (a) 49000 (b) 490 (c) 4900
  4. 4.Best estimate of 206 + 453? (a) 900 (b) 700 (c) 500
  5. 5.Best estimate of 302 + 329? (a) 800 (b) 400 (c) 600
  6. 6.Best estimate of 88 × 57? (a) 5400 (b) 540 (c) 54000
  7. 7.Best estimate of 44 × 49? (a) 2000 (b) 200 (c) 20000
  8. 8.Best estimate of 59 × 57? (a) 3600 (b) 360 (c) 36000
  9. 9.Best estimate of 69 × 31? (a) 21000 (b) 2100 (c) 210
  10. 10.Best estimate of 71 × 43? (a) 2800 (b) 28000 (c) 280
  11. 11.Best estimate of 129 + 363? (a) 700 (b) 300 (c) 500
  12. 12.Best estimate of 29 × 39? (a) 120 (b) 12000 (c) 1200
  13. 13.Best estimate of 17 × 96? (a) 200 (b) 2000 (c) 20000
  14. 14.Best estimate of 57 × 67? (a) 420 (b) 4200 (c) 42000
  15. 15.Best estimate of 60 × 74? (a) 42000 (b) 420 (c) 4200
  16. 16.Best estimate of 38 × 34? (a) 12000 (b) 120 (c) 1200
  17. 17.Best estimate of 560 + 694? (a) 1100 (b) 1300 (c) 1500
  18. 18.Best estimate of 569 + 143? (a) 900 (b) 700 (c) 500
  19. 19.Best estimate of 176 + 295? (a) 300 (b) 700 (c) 500
  20. 20.Best estimate of 228 + 360? (a) 800 (b) 400 (c) 600
  21. 21.Best estimate of 92 × 18? (a) 180 (b) 1800 (c) 18000
  22. 22.Best estimate of 86 × 61? (a) 5400 (b) 54000 (c) 540
  23. 23.Best estimate of 81 × 86? (a) 72000 (b) 720 (c) 7200
  24. 24.Best estimate of 92 × 82? (a) 7200 (b) 720 (c) 72000
  25. 25.Best estimate of 749 + 384? (a) 900 (b) 1300 (c) 1100
  26. 26.Best estimate of 266 + 391? (a) 900 (b) 500 (c) 700
  27. 27.Best estimate of 498 + 651? (a) 1400 (b) 1200 (c) 1000
  28. 28.Best estimate of 69 × 14? (a) 70 (b) 7000 (c) 700
  29. 29.Best estimate of 54 × 80? (a) 400 (b) 4000 (c) 40000
  30. 30.Best estimate of 243 + 166? (a) 600 (b) 400 (c) 200
  31. 31.Best estimate of 542 + 503? (a) 1000 (b) 800 (c) 1200
  32. 32.Best estimate of 134 + 339? (a) 200 (b) 600 (c) 400
  33. 33.Best estimate of 284 + 519? (a) 800 (b) 600 (c) 1000
  34. 34.Best estimate of 496 + 847? (a) 1300 (b) 1100 (c) 1500
  35. 35.Best estimate of 832 + 800? (a) 1800 (b) 1600 (c) 1400
  36. 36.Best estimate of 74 × 71? (a) 4900 (b) 49000 (c) 490
  37. 37.Best estimate of 93 × 53? (a) 450 (b) 45000 (c) 4500
  38. 38.Best estimate of 21 × 92? (a) 18000 (b) 180 (c) 1800
  39. 39.Best estimate of 87 × 66? (a) 630 (b) 6300 (c) 63000
  40. 40.Best estimate of 792 + 233? (a) 1200 (b) 1000 (c) 800

Answer key

  1. 1200
  2. 1500
  3. 4900
  4. 700
  5. 600
  6. 5400
  7. 2000
  8. 3600
  9. 2100
  10. 2800
  11. 500
  12. 1200
  13. 2000
  14. 4200
  15. 4200
  16. 1200
  17. 1300
  18. 700
  19. 500
  20. 600
  21. 1800
  22. 5400
  23. 7200
  24. 7200
  25. 1100
  26. 700
  27. 1200
  28. 700
  29. 4000
  30. 400
  31. 1000
  32. 400
  33. 800
  34. 1300
  35. 1600
  36. 4900
  37. 4500
  38. 1800
  39. 6300
  40. 1000

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