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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 720 · 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 48 × 97? (a) 50000 (b) 5000 (c) 500
  2. 2.Best estimate of 88 × 56? (a) 54000 (b) 540 (c) 5400
  3. 3.Best estimate of 59 × 92? (a) 54000 (b) 540 (c) 5400
  4. 4.Best estimate of 63 × 92? (a) 54000 (b) 540 (c) 5400
  5. 5.Best estimate of 244 + 265? (a) 500 (b) 700 (c) 300
  6. 6.Best estimate of 299 + 288? (a) 600 (b) 800 (c) 400
  7. 7.Best estimate of 96 × 34? (a) 3000 (b) 30000 (c) 300
  8. 8.Best estimate of 26 × 40? (a) 12000 (b) 1200 (c) 120
  9. 9.Best estimate of 221 + 661? (a) 900 (b) 700 (c) 1100
  10. 10.Best estimate of 78 × 23? (a) 1600 (b) 160 (c) 16000
  11. 11.Best estimate of 66 × 42? (a) 280 (b) 28000 (c) 2800
  12. 12.Best estimate of 38 × 79? (a) 320 (b) 32000 (c) 3200
  13. 13.Best estimate of 96 × 57? (a) 6000 (b) 600 (c) 60000
  14. 14.Best estimate of 822 + 704? (a) 1500 (b) 1300 (c) 1700
  15. 15.Best estimate of 731 + 353? (a) 1300 (b) 900 (c) 1100
  16. 16.Best estimate of 58 × 92? (a) 54000 (b) 540 (c) 5400
  17. 17.Best estimate of 245 + 442? (a) 600 (b) 800 (c) 400
  18. 18.Best estimate of 86 × 36? (a) 36000 (b) 360 (c) 3600
  19. 19.Best estimate of 636 + 764? (a) 1600 (b) 1200 (c) 1400
  20. 20.Best estimate of 18 × 21? (a) 400 (b) 4000 (c) 40
  21. 21.Best estimate of 96 × 58? (a) 600 (b) 60000 (c) 6000
  22. 22.Best estimate of 826 + 477? (a) 1300 (b) 1500 (c) 1100
  23. 23.Best estimate of 31 × 96? (a) 3000 (b) 300 (c) 30000
  24. 24.Best estimate of 122 + 239? (a) 300 (b) 100 (c) 500
  25. 25.Best estimate of 19 × 56? (a) 120 (b) 1200 (c) 12000
  26. 26.Best estimate of 54 × 18? (a) 100 (b) 10000 (c) 1000
  27. 27.Best estimate of 70 × 56? (a) 420 (b) 4200 (c) 42000
  28. 28.Best estimate of 168 + 773? (a) 800 (b) 1000 (c) 1200
  29. 29.Best estimate of 39 × 86? (a) 36000 (b) 3600 (c) 360
  30. 30.Best estimate of 20 × 47? (a) 100 (b) 10000 (c) 1000
  31. 31.Best estimate of 745 + 783? (a) 1500 (b) 1700 (c) 1300
  32. 32.Best estimate of 84 × 37? (a) 3200 (b) 32000 (c) 320
  33. 33.Best estimate of 17 × 39? (a) 800 (b) 8000 (c) 80
  34. 34.Best estimate of 185 + 772? (a) 1000 (b) 800 (c) 1200
  35. 35.Best estimate of 81 × 40? (a) 320 (b) 3200 (c) 32000
  36. 36.Best estimate of 94 × 47? (a) 4500 (b) 45000 (c) 450
  37. 37.Best estimate of 179 + 471? (a) 500 (b) 700 (c) 900
  38. 38.Best estimate of 281 + 654? (a) 1000 (b) 1200 (c) 800
  39. 39.Best estimate of 42 × 47? (a) 200 (b) 2000 (c) 20000
  40. 40.Best estimate of 77 × 83? (a) 64000 (b) 6400 (c) 640

Answer key

  1. 5000
  2. 5400
  3. 5400
  4. 5400
  5. 500
  6. 600
  7. 3000
  8. 1200
  9. 900
  10. 1600
  11. 2800
  12. 3200
  13. 6000
  14. 1500
  15. 1100
  16. 5400
  17. 600
  18. 3600
  19. 1400
  20. 400
  21. 6000
  22. 1300
  23. 3000
  24. 300
  25. 1200
  26. 1000
  27. 4200
  28. 1000
  29. 3600
  30. 1000
  31. 1500
  32. 3200
  33. 800
  34. 1000
  35. 3200
  36. 4500
  37. 700
  38. 1000
  39. 2000
  40. 6400

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