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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 740 · 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 63 × 26? (a) 1800 (b) 18000 (c) 180
  2. 2.Best estimate of 223 + 488? (a) 900 (b) 500 (c) 700
  3. 3.Best estimate of 67 × 34? (a) 21000 (b) 210 (c) 2100
  4. 4.Best estimate of 38 × 36? (a) 16000 (b) 160 (c) 1600
  5. 5.Best estimate of 480 + 709? (a) 1200 (b) 1400 (c) 1000
  6. 6.Best estimate of 151 + 388? (a) 400 (b) 600 (c) 800
  7. 7.Best estimate of 41 × 48? (a) 2000 (b) 200 (c) 20000
  8. 8.Best estimate of 488 + 682? (a) 1000 (b) 1200 (c) 1400
  9. 9.Best estimate of 127 + 525? (a) 600 (b) 400 (c) 800
  10. 10.Best estimate of 74 × 44? (a) 280 (b) 2800 (c) 28000
  11. 11.Best estimate of 36 × 79? (a) 320 (b) 3200 (c) 32000
  12. 12.Best estimate of 280 + 127? (a) 400 (b) 600 (c) 200
  13. 13.Best estimate of 42 × 96? (a) 40000 (b) 400 (c) 4000
  14. 14.Best estimate of 90 × 63? (a) 54000 (b) 5400 (c) 540
  15. 15.Best estimate of 130 + 859? (a) 800 (b) 1200 (c) 1000
  16. 16.Best estimate of 24 × 46? (a) 1000 (b) 10000 (c) 100
  17. 17.Best estimate of 22 × 81? (a) 16000 (b) 160 (c) 1600
  18. 18.Best estimate of 48 × 43? (a) 200 (b) 2000 (c) 20000
  19. 19.Best estimate of 24 × 34? (a) 600 (b) 6000 (c) 60
  20. 20.Best estimate of 27 × 16? (a) 60 (b) 600 (c) 6000
  21. 21.Best estimate of 70 × 60? (a) 420 (b) 4200 (c) 42000
  22. 22.Best estimate of 30 × 20? (a) 6000 (b) 600 (c) 60
  23. 23.Best estimate of 60 × 84? (a) 480 (b) 48000 (c) 4800
  24. 24.Best estimate of 307 + 610? (a) 900 (b) 1100 (c) 700
  25. 25.Best estimate of 73 × 74? (a) 490 (b) 49000 (c) 4900
  26. 26.Best estimate of 53 × 48? (a) 2500 (b) 250 (c) 25000
  27. 27.Best estimate of 248 + 360? (a) 400 (b) 800 (c) 600
  28. 28.Best estimate of 406 + 418? (a) 800 (b) 600 (c) 1000
  29. 29.Best estimate of 847 + 129? (a) 1100 (b) 700 (c) 900
  30. 30.Best estimate of 41 × 57? (a) 240 (b) 24000 (c) 2400
  31. 31.Best estimate of 48 × 86? (a) 4500 (b) 450 (c) 45000
  32. 32.Best estimate of 53 × 88? (a) 450 (b) 45000 (c) 4500
  33. 33.Best estimate of 846 + 497? (a) 1100 (b) 1300 (c) 1500
  34. 34.Best estimate of 19 × 21? (a) 400 (b) 40 (c) 4000
  35. 35.Best estimate of 604 + 601? (a) 1400 (b) 1000 (c) 1200
  36. 36.Best estimate of 483 + 660? (a) 1400 (b) 1000 (c) 1200
  37. 37.Best estimate of 797 + 348? (a) 1100 (b) 900 (c) 1300
  38. 38.Best estimate of 731 + 169? (a) 900 (b) 1100 (c) 700
  39. 39.Best estimate of 96 × 22? (a) 200 (b) 20000 (c) 2000
  40. 40.Best estimate of 349 + 503? (a) 1000 (b) 800 (c) 600

Answer key

  1. 1800
  2. 700
  3. 2100
  4. 1600
  5. 1200
  6. 600
  7. 2000
  8. 1200
  9. 600
  10. 2800
  11. 3200
  12. 400
  13. 4000
  14. 5400
  15. 1000
  16. 1000
  17. 1600
  18. 2000
  19. 600
  20. 600
  21. 4200
  22. 600
  23. 4800
  24. 900
  25. 4900
  26. 2500
  27. 600
  28. 800
  29. 900
  30. 2400
  31. 4500
  32. 4500
  33. 1300
  34. 400
  35. 1200
  36. 1200
  37. 1100
  38. 900
  39. 2000
  40. 800

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