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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 734 · 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 88 × 96? (a) 90000 (b) 900 (c) 9000
  2. 2.Best estimate of 267 + 124? (a) 400 (b) 600 (c) 200
  3. 3.Best estimate of 93 × 67? (a) 63000 (b) 6300 (c) 630
  4. 4.Best estimate of 747 + 420? (a) 900 (b) 1300 (c) 1100
  5. 5.Best estimate of 72 × 88? (a) 630 (b) 6300 (c) 63000
  6. 6.Best estimate of 36 × 82? (a) 3200 (b) 320 (c) 32000
  7. 7.Best estimate of 24 × 26? (a) 600 (b) 6000 (c) 60
  8. 8.Best estimate of 87 × 46? (a) 4500 (b) 450 (c) 45000
  9. 9.Best estimate of 178 + 840? (a) 1000 (b) 800 (c) 1200
  10. 10.Best estimate of 34 × 81? (a) 240 (b) 24000 (c) 2400
  11. 11.Best estimate of 193 + 614? (a) 800 (b) 600 (c) 1000
  12. 12.Best estimate of 43 × 33? (a) 12000 (b) 1200 (c) 120
  13. 13.Best estimate of 153 + 686? (a) 700 (b) 1100 (c) 900
  14. 14.Best estimate of 279 + 745? (a) 1200 (b) 1000 (c) 800
  15. 15.Best estimate of 619 + 487? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 96 × 38? (a) 4000 (b) 40000 (c) 400
  17. 17.Best estimate of 305 + 765? (a) 900 (b) 1300 (c) 1100
  18. 18.Best estimate of 46 × 92? (a) 4500 (b) 450 (c) 45000
  19. 19.Best estimate of 76 × 81? (a) 640 (b) 64000 (c) 6400
  20. 20.Best estimate of 865 + 242? (a) 1100 (b) 1300 (c) 900
  21. 21.Best estimate of 483 + 348? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 70 × 29? (a) 21000 (b) 2100 (c) 210
  23. 23.Best estimate of 66 × 67? (a) 4900 (b) 490 (c) 49000
  24. 24.Best estimate of 49 × 28? (a) 150 (b) 1500 (c) 15000
  25. 25.Best estimate of 64 × 59? (a) 3600 (b) 360 (c) 36000
  26. 26.Best estimate of 204 + 502? (a) 700 (b) 500 (c) 900
  27. 27.Best estimate of 46 × 26? (a) 15000 (b) 150 (c) 1500
  28. 28.Best estimate of 43 × 44? (a) 16000 (b) 1600 (c) 160
  29. 29.Best estimate of 28 × 98? (a) 300 (b) 30000 (c) 3000
  30. 30.Best estimate of 745 + 360? (a) 1100 (b) 900 (c) 1300
  31. 31.Best estimate of 88 × 14? (a) 900 (b) 9000 (c) 90
  32. 32.Best estimate of 788 + 146? (a) 700 (b) 900 (c) 1100
  33. 33.Best estimate of 165 + 182? (a) 200 (b) 400 (c) 600
  34. 34.Best estimate of 17 × 31? (a) 60 (b) 6000 (c) 600
  35. 35.Best estimate of 92 × 43? (a) 36000 (b) 3600 (c) 360
  36. 36.Best estimate of 799 + 434? (a) 1400 (b) 1000 (c) 1200
  37. 37.Best estimate of 710 + 608? (a) 1100 (b) 1300 (c) 1500
  38. 38.Best estimate of 327 + 661? (a) 1000 (b) 1200 (c) 800
  39. 39.Best estimate of 137 + 359? (a) 700 (b) 500 (c) 300
  40. 40.Best estimate of 63 × 73? (a) 420 (b) 42000 (c) 4200

Answer key

  1. 9000
  2. 400
  3. 6300
  4. 1100
  5. 6300
  6. 3200
  7. 600
  8. 4500
  9. 1000
  10. 2400
  11. 800
  12. 1200
  13. 900
  14. 1000
  15. 1100
  16. 4000
  17. 1100
  18. 4500
  19. 6400
  20. 1100
  21. 800
  22. 2100
  23. 4900
  24. 1500
  25. 3600
  26. 700
  27. 1500
  28. 1600
  29. 3000
  30. 1100
  31. 900
  32. 900
  33. 400
  34. 600
  35. 3600
  36. 1200
  37. 1300
  38. 1000
  39. 500
  40. 4200

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