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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 372 · 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 44 × 26? (a) 1200 (b) 12000 (c) 120
  2. 2.Best estimate of 155 + 763? (a) 800 (b) 1200 (c) 1000
  3. 3.Best estimate of 96 × 56? (a) 60000 (b) 6000 (c) 600
  4. 4.Best estimate of 409 + 427? (a) 1000 (b) 600 (c) 800
  5. 5.Best estimate of 786 + 166? (a) 1200 (b) 1000 (c) 800
  6. 6.Best estimate of 66 × 23? (a) 140 (b) 14000 (c) 1400
  7. 7.Best estimate of 87 × 22? (a) 1800 (b) 180 (c) 18000
  8. 8.Best estimate of 252 + 517? (a) 800 (b) 600 (c) 1000
  9. 9.Best estimate of 477 + 235? (a) 900 (b) 500 (c) 700
  10. 10.Best estimate of 622 + 214? (a) 600 (b) 800 (c) 1000
  11. 11.Best estimate of 79 × 92? (a) 72000 (b) 7200 (c) 720
  12. 12.Best estimate of 505 + 435? (a) 700 (b) 1100 (c) 900
  13. 13.Best estimate of 87 × 14? (a) 9000 (b) 90 (c) 900
  14. 14.Best estimate of 49 × 18? (a) 10000 (b) 100 (c) 1000
  15. 15.Best estimate of 22 × 21? (a) 400 (b) 4000 (c) 40
  16. 16.Best estimate of 46 × 61? (a) 3000 (b) 300 (c) 30000
  17. 17.Best estimate of 42 × 18? (a) 800 (b) 8000 (c) 80
  18. 18.Best estimate of 21 × 47? (a) 1000 (b) 100 (c) 10000
  19. 19.Best estimate of 63 × 62? (a) 36000 (b) 360 (c) 3600
  20. 20.Best estimate of 184 + 286? (a) 500 (b) 700 (c) 300
  21. 21.Best estimate of 516 + 186? (a) 700 (b) 500 (c) 900
  22. 22.Best estimate of 419 + 866? (a) 1300 (b) 1500 (c) 1100
  23. 23.Best estimate of 14 × 53? (a) 500 (b) 50 (c) 5000
  24. 24.Best estimate of 521 + 370? (a) 900 (b) 1100 (c) 700
  25. 25.Best estimate of 147 + 747? (a) 600 (b) 800 (c) 1000
  26. 26.Best estimate of 469 + 869? (a) 1600 (b) 1200 (c) 1400
  27. 27.Best estimate of 96 × 26? (a) 30000 (b) 300 (c) 3000
  28. 28.Best estimate of 57 × 34? (a) 180 (b) 18000 (c) 1800
  29. 29.Best estimate of 659 + 465? (a) 1000 (b) 1200 (c) 1400
  30. 30.Best estimate of 44 × 49? (a) 2000 (b) 20000 (c) 200
  31. 31.Best estimate of 91 × 26? (a) 27000 (b) 270 (c) 2700
  32. 32.Best estimate of 61 × 51? (a) 3000 (b) 300 (c) 30000
  33. 33.Best estimate of 569 + 843? (a) 1600 (b) 1200 (c) 1400
  34. 34.Best estimate of 531 + 126? (a) 600 (b) 400 (c) 800
  35. 35.Best estimate of 54 × 26? (a) 150 (b) 1500 (c) 15000
  36. 36.Best estimate of 13 × 33? (a) 300 (b) 3000 (c) 30
  37. 37.Best estimate of 276 + 148? (a) 200 (b) 400 (c) 600
  38. 38.Best estimate of 654 + 529? (a) 1200 (b) 1400 (c) 1000
  39. 39.Best estimate of 63 × 48? (a) 3000 (b) 30000 (c) 300
  40. 40.Best estimate of 558 + 396? (a) 1000 (b) 800 (c) 1200

Answer key

  1. 1200
  2. 1000
  3. 6000
  4. 800
  5. 1000
  6. 1400
  7. 1800
  8. 800
  9. 700
  10. 800
  11. 7200
  12. 900
  13. 900
  14. 1000
  15. 400
  16. 3000
  17. 800
  18. 1000
  19. 3600
  20. 500
  21. 700
  22. 1300
  23. 500
  24. 900
  25. 800
  26. 1400
  27. 3000
  28. 1800
  29. 1200
  30. 2000
  31. 2700
  32. 3000
  33. 1400
  34. 600
  35. 1500
  36. 300
  37. 400
  38. 1200
  39. 3000
  40. 1000

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