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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 332 · 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 14 × 62? (a) 60 (b) 6000 (c) 600
  2. 2.Best estimate of 81 × 57? (a) 48000 (b) 480 (c) 4800
  3. 3.Best estimate of 370 + 459? (a) 900 (b) 700 (c) 1100
  4. 4.Best estimate of 92 × 80? (a) 72000 (b) 7200 (c) 720
  5. 5.Best estimate of 137 + 719? (a) 1000 (b) 800 (c) 600
  6. 6.Best estimate of 605 + 223? (a) 800 (b) 1000 (c) 600
  7. 7.Best estimate of 13 × 28? (a) 3000 (b) 30 (c) 300
  8. 8.Best estimate of 622 + 819? (a) 1400 (b) 1600 (c) 1200
  9. 9.Best estimate of 14 × 46? (a) 500 (b) 5000 (c) 50
  10. 10.Best estimate of 33 × 32? (a) 90 (b) 9000 (c) 900
  11. 11.Best estimate of 26 × 94? (a) 270 (b) 27000 (c) 2700
  12. 12.Best estimate of 46 × 21? (a) 1000 (b) 10000 (c) 100
  13. 13.Best estimate of 33 × 66? (a) 210 (b) 2100 (c) 21000
  14. 14.Best estimate of 16 × 37? (a) 8000 (b) 80 (c) 800
  15. 15.Best estimate of 31 × 44? (a) 120 (b) 1200 (c) 12000
  16. 16.Best estimate of 681 + 321? (a) 1200 (b) 1000 (c) 800
  17. 17.Best estimate of 211 + 816? (a) 1200 (b) 1000 (c) 800
  18. 18.Best estimate of 518 + 670? (a) 1200 (b) 1000 (c) 1400
  19. 19.Best estimate of 21 × 58? (a) 1200 (b) 120 (c) 12000
  20. 20.Best estimate of 31 × 77? (a) 240 (b) 24000 (c) 2400
  21. 21.Best estimate of 537 + 299? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 93 × 37? (a) 360 (b) 3600 (c) 36000
  23. 23.Best estimate of 763 + 647? (a) 1200 (b) 1600 (c) 1400
  24. 24.Best estimate of 411 + 288? (a) 900 (b) 700 (c) 500
  25. 25.Best estimate of 46 × 42? (a) 200 (b) 2000 (c) 20000
  26. 26.Best estimate of 32 × 46? (a) 1500 (b) 150 (c) 15000
  27. 27.Best estimate of 16 × 23? (a) 40 (b) 4000 (c) 400
  28. 28.Best estimate of 36 × 92? (a) 36000 (b) 3600 (c) 360
  29. 29.Best estimate of 818 + 281? (a) 1300 (b) 1100 (c) 900
  30. 30.Best estimate of 62 × 61? (a) 360 (b) 36000 (c) 3600
  31. 31.Best estimate of 42 × 64? (a) 240 (b) 2400 (c) 24000
  32. 32.Best estimate of 595 + 630? (a) 1000 (b) 1200 (c) 1400
  33. 33.Best estimate of 77 × 54? (a) 400 (b) 4000 (c) 40000
  34. 34.Best estimate of 47 × 12? (a) 50 (b) 500 (c) 5000
  35. 35.Best estimate of 197 + 341? (a) 700 (b) 300 (c) 500
  36. 36.Best estimate of 68 × 92? (a) 63000 (b) 6300 (c) 630
  37. 37.Best estimate of 149 + 844? (a) 900 (b) 700 (c) 1100
  38. 38.Best estimate of 269 + 717? (a) 800 (b) 1200 (c) 1000
  39. 39.Best estimate of 76 × 91? (a) 7200 (b) 72000 (c) 720
  40. 40.Best estimate of 736 + 299? (a) 800 (b) 1200 (c) 1000

Answer key

  1. 600
  2. 4800
  3. 900
  4. 7200
  5. 800
  6. 800
  7. 300
  8. 1400
  9. 500
  10. 900
  11. 2700
  12. 1000
  13. 2100
  14. 800
  15. 1200
  16. 1000
  17. 1000
  18. 1200
  19. 1200
  20. 2400
  21. 800
  22. 3600
  23. 1400
  24. 700
  25. 2000
  26. 1500
  27. 400
  28. 3600
  29. 1100
  30. 3600
  31. 2400
  32. 1200
  33. 4000
  34. 500
  35. 500
  36. 6300
  37. 900
  38. 1000
  39. 7200
  40. 1000

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