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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 338 · 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 548 + 208? (a) 500 (b) 700 (c) 900
  2. 2.Best estimate of 12 × 22? (a) 20 (b) 2000 (c) 200
  3. 3.Best estimate of 207 + 481? (a) 900 (b) 500 (c) 700
  4. 4.Best estimate of 849 + 174? (a) 800 (b) 1200 (c) 1000
  5. 5.Best estimate of 77 × 71? (a) 5600 (b) 56000 (c) 560
  6. 6.Best estimate of 82 × 29? (a) 2400 (b) 24000 (c) 240
  7. 7.Best estimate of 17 × 16? (a) 400 (b) 40 (c) 4000
  8. 8.Best estimate of 777 + 565? (a) 1400 (b) 1600 (c) 1200
  9. 9.Best estimate of 647 + 137? (a) 700 (b) 500 (c) 900
  10. 10.Best estimate of 16 × 41? (a) 8000 (b) 800 (c) 80
  11. 11.Best estimate of 13 × 90? (a) 9000 (b) 900 (c) 90
  12. 12.Best estimate of 197 + 562? (a) 800 (b) 600 (c) 1000
  13. 13.Best estimate of 431 + 879? (a) 1300 (b) 1500 (c) 1100
  14. 14.Best estimate of 857 + 827? (a) 1900 (b) 1500 (c) 1700
  15. 15.Best estimate of 247 + 519? (a) 900 (b) 700 (c) 500
  16. 16.Best estimate of 328 + 779? (a) 900 (b) 1100 (c) 1300
  17. 17.Best estimate of 317 + 224? (a) 500 (b) 700 (c) 300
  18. 18.Best estimate of 76 × 62? (a) 4800 (b) 48000 (c) 480
  19. 19.Best estimate of 13 × 32? (a) 30 (b) 3000 (c) 300
  20. 20.Best estimate of 40 × 96? (a) 40000 (b) 4000 (c) 400
  21. 21.Best estimate of 21 × 16? (a) 40 (b) 400 (c) 4000
  22. 22.Best estimate of 871 + 592? (a) 1300 (b) 1700 (c) 1500
  23. 23.Best estimate of 32 × 23? (a) 6000 (b) 600 (c) 60
  24. 24.Best estimate of 305 + 194? (a) 700 (b) 300 (c) 500
  25. 25.Best estimate of 86 × 19? (a) 1800 (b) 180 (c) 18000
  26. 26.Best estimate of 628 + 313? (a) 900 (b) 1100 (c) 700
  27. 27.Best estimate of 519 + 556? (a) 1300 (b) 900 (c) 1100
  28. 28.Best estimate of 705 + 149? (a) 600 (b) 1000 (c) 800
  29. 29.Best estimate of 28 × 23? (a) 600 (b) 6000 (c) 60
  30. 30.Best estimate of 694 + 821? (a) 1300 (b) 1700 (c) 1500
  31. 31.Best estimate of 46 × 47? (a) 25000 (b) 250 (c) 2500
  32. 32.Best estimate of 190 + 189? (a) 400 (b) 200 (c) 600
  33. 33.Best estimate of 255 + 506? (a) 600 (b) 800 (c) 1000
  34. 34.Best estimate of 74 × 90? (a) 63000 (b) 6300 (c) 630
  35. 35.Best estimate of 383 + 259? (a) 500 (b) 700 (c) 900
  36. 36.Best estimate of 668 + 756? (a) 1700 (b) 1300 (c) 1500
  37. 37.Best estimate of 12 × 52? (a) 5000 (b) 50 (c) 500
  38. 38.Best estimate of 136 + 200? (a) 300 (b) 100 (c) 500
  39. 39.Best estimate of 62 × 56? (a) 36000 (b) 3600 (c) 360
  40. 40.Best estimate of 88 × 29? (a) 27000 (b) 2700 (c) 270

Answer key

  1. 700
  2. 200
  3. 700
  4. 1000
  5. 5600
  6. 2400
  7. 400
  8. 1400
  9. 700
  10. 800
  11. 900
  12. 800
  13. 1300
  14. 1700
  15. 700
  16. 1100
  17. 500
  18. 4800
  19. 300
  20. 4000
  21. 400
  22. 1500
  23. 600
  24. 500
  25. 1800
  26. 900
  27. 1100
  28. 800
  29. 600
  30. 1500
  31. 2500
  32. 400
  33. 800
  34. 6300
  35. 700
  36. 1500
  37. 500
  38. 300
  39. 3600
  40. 2700

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