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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 304 · 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 21 × 40? (a) 800 (b) 8000 (c) 80
  2. 2.Best estimate of 233 + 843? (a) 1200 (b) 1000 (c) 800
  3. 3.Best estimate of 36 × 77? (a) 320 (b) 32000 (c) 3200
  4. 4.Best estimate of 414 + 826? (a) 1400 (b) 1000 (c) 1200
  5. 5.Best estimate of 16 × 64? (a) 120 (b) 12000 (c) 1200
  6. 6.Best estimate of 145 + 223? (a) 300 (b) 100 (c) 500
  7. 7.Best estimate of 27 × 90? (a) 2700 (b) 27000 (c) 270
  8. 8.Best estimate of 867 + 665? (a) 1800 (b) 1400 (c) 1600
  9. 9.Best estimate of 54 × 27? (a) 1500 (b) 15000 (c) 150
  10. 10.Best estimate of 33 × 16? (a) 6000 (b) 60 (c) 600
  11. 11.Best estimate of 775 + 600? (a) 1600 (b) 1200 (c) 1400
  12. 12.Best estimate of 17 × 58? (a) 1200 (b) 12000 (c) 120
  13. 13.Best estimate of 700 + 713? (a) 1600 (b) 1200 (c) 1400
  14. 14.Best estimate of 16 × 49? (a) 1000 (b) 10000 (c) 100
  15. 15.Best estimate of 67 × 69? (a) 4900 (b) 490 (c) 49000
  16. 16.Best estimate of 38 × 26? (a) 120 (b) 1200 (c) 12000
  17. 17.Best estimate of 804 + 638? (a) 1200 (b) 1400 (c) 1600
  18. 18.Best estimate of 147 + 611? (a) 500 (b) 900 (c) 700
  19. 19.Best estimate of 33 × 77? (a) 240 (b) 2400 (c) 24000
  20. 20.Best estimate of 43 × 89? (a) 360 (b) 3600 (c) 36000
  21. 21.Best estimate of 64 × 66? (a) 42000 (b) 420 (c) 4200
  22. 22.Best estimate of 19 × 61? (a) 12000 (b) 120 (c) 1200
  23. 23.Best estimate of 383 + 228? (a) 600 (b) 800 (c) 400
  24. 24.Best estimate of 29 × 72? (a) 21000 (b) 2100 (c) 210
  25. 25.Best estimate of 53 × 61? (a) 30000 (b) 3000 (c) 300
  26. 26.Best estimate of 28 × 39? (a) 12000 (b) 120 (c) 1200
  27. 27.Best estimate of 791 + 740? (a) 1500 (b) 1700 (c) 1300
  28. 28.Best estimate of 16 × 69? (a) 140 (b) 1400 (c) 14000
  29. 29.Best estimate of 335 + 504? (a) 600 (b) 800 (c) 1000
  30. 30.Best estimate of 70 × 76? (a) 5600 (b) 56000 (c) 560
  31. 31.Best estimate of 546 + 773? (a) 1300 (b) 1500 (c) 1100
  32. 32.Best estimate of 799 + 288? (a) 900 (b) 1300 (c) 1100
  33. 33.Best estimate of 43 × 84? (a) 3200 (b) 320 (c) 32000
  34. 34.Best estimate of 37 × 49? (a) 2000 (b) 200 (c) 20000
  35. 35.Best estimate of 865 + 195? (a) 1100 (b) 900 (c) 1300
  36. 36.Best estimate of 21 × 28? (a) 60 (b) 6000 (c) 600
  37. 37.Best estimate of 804 + 662? (a) 1300 (b) 1700 (c) 1500
  38. 38.Best estimate of 66 × 44? (a) 28000 (b) 280 (c) 2800
  39. 39.Best estimate of 26 × 90? (a) 27000 (b) 270 (c) 2700
  40. 40.Best estimate of 14 × 96? (a) 1000 (b) 10000 (c) 100

Answer key

  1. 800
  2. 1000
  3. 3200
  4. 1200
  5. 1200
  6. 300
  7. 2700
  8. 1600
  9. 1500
  10. 600
  11. 1400
  12. 1200
  13. 1400
  14. 1000
  15. 4900
  16. 1200
  17. 1400
  18. 700
  19. 2400
  20. 3600
  21. 4200
  22. 1200
  23. 600
  24. 2100
  25. 3000
  26. 1200
  27. 1500
  28. 1400
  29. 800
  30. 5600
  31. 1300
  32. 1100
  33. 3200
  34. 2000
  35. 1100
  36. 600
  37. 1500
  38. 2800
  39. 2700
  40. 1000

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