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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 329 · 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 252 + 541? (a) 600 (b) 800 (c) 1000
  2. 2.Best estimate of 12 × 46? (a) 50 (b) 5000 (c) 500
  3. 3.Best estimate of 417 + 209? (a) 400 (b) 600 (c) 800
  4. 4.Best estimate of 47 × 49? (a) 25000 (b) 2500 (c) 250
  5. 5.Best estimate of 337 + 716? (a) 1000 (b) 1200 (c) 800
  6. 6.Best estimate of 753 + 124? (a) 700 (b) 900 (c) 1100
  7. 7.Best estimate of 19 × 57? (a) 12000 (b) 1200 (c) 120
  8. 8.Best estimate of 29 × 92? (a) 270 (b) 2700 (c) 27000
  9. 9.Best estimate of 171 + 277? (a) 300 (b) 500 (c) 700
  10. 10.Best estimate of 60 × 31? (a) 1800 (b) 18000 (c) 180
  11. 11.Best estimate of 56 × 88? (a) 5400 (b) 54000 (c) 540
  12. 12.Best estimate of 293 + 713? (a) 1000 (b) 800 (c) 1200
  13. 13.Best estimate of 36 × 42? (a) 16000 (b) 1600 (c) 160
  14. 14.Best estimate of 247 + 156? (a) 600 (b) 400 (c) 200
  15. 15.Best estimate of 50 × 29? (a) 15000 (b) 150 (c) 1500
  16. 16.Best estimate of 30 × 29? (a) 9000 (b) 90 (c) 900
  17. 17.Best estimate of 14 × 60? (a) 6000 (b) 600 (c) 60
  18. 18.Best estimate of 22 × 18? (a) 400 (b) 40 (c) 4000
  19. 19.Best estimate of 821 + 401? (a) 1000 (b) 1200 (c) 1400
  20. 20.Best estimate of 22 × 39? (a) 8000 (b) 800 (c) 80
  21. 21.Best estimate of 842 + 153? (a) 1200 (b) 1000 (c) 800
  22. 22.Best estimate of 26 × 98? (a) 300 (b) 30000 (c) 3000
  23. 23.Best estimate of 20 × 17? (a) 4000 (b) 400 (c) 40
  24. 24.Best estimate of 77 × 16? (a) 1600 (b) 160 (c) 16000
  25. 25.Best estimate of 19 × 77? (a) 1600 (b) 16000 (c) 160
  26. 26.Best estimate of 478 + 284? (a) 600 (b) 1000 (c) 800
  27. 27.Best estimate of 613 + 540? (a) 1100 (b) 1300 (c) 900
  28. 28.Best estimate of 248 + 202? (a) 400 (b) 600 (c) 200
  29. 29.Best estimate of 93 × 36? (a) 360 (b) 3600 (c) 36000
  30. 30.Best estimate of 586 + 695? (a) 1500 (b) 1100 (c) 1300
  31. 31.Best estimate of 261 + 596? (a) 700 (b) 900 (c) 1100
  32. 32.Best estimate of 42 × 68? (a) 2800 (b) 280 (c) 28000
  33. 33.Best estimate of 86 × 46? (a) 4500 (b) 450 (c) 45000
  34. 34.Best estimate of 757 + 204? (a) 1000 (b) 1200 (c) 800
  35. 35.Best estimate of 76 × 32? (a) 240 (b) 2400 (c) 24000
  36. 36.Best estimate of 728 + 588? (a) 1500 (b) 1300 (c) 1100
  37. 37.Best estimate of 449 + 421? (a) 600 (b) 800 (c) 1000
  38. 38.Best estimate of 34 × 23? (a) 600 (b) 6000 (c) 60
  39. 39.Best estimate of 28 × 96? (a) 300 (b) 30000 (c) 3000
  40. 40.Best estimate of 441 + 744? (a) 1100 (b) 1300 (c) 900

Answer key

  1. 800
  2. 500
  3. 600
  4. 2500
  5. 1000
  6. 900
  7. 1200
  8. 2700
  9. 500
  10. 1800
  11. 5400
  12. 1000
  13. 1600
  14. 400
  15. 1500
  16. 900
  17. 600
  18. 400
  19. 1200
  20. 800
  21. 1000
  22. 3000
  23. 400
  24. 1600
  25. 1600
  26. 800
  27. 1100
  28. 400
  29. 3600
  30. 1300
  31. 900
  32. 2800
  33. 4500
  34. 1000
  35. 2400
  36. 1300
  37. 800
  38. 600
  39. 3000
  40. 1100

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