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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 283 · 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 97 × 30? (a) 300 (b) 30000 (c) 3000
  2. 2.Best estimate of 48 × 43? (a) 20000 (b) 2000 (c) 200
  3. 3.Best estimate of 70 × 19? (a) 14000 (b) 1400 (c) 140
  4. 4.Best estimate of 671 + 266? (a) 1200 (b) 1000 (c) 800
  5. 5.Best estimate of 558 + 705? (a) 1300 (b) 1100 (c) 1500
  6. 6.Best estimate of 724 + 310? (a) 1000 (b) 1200 (c) 800
  7. 7.Best estimate of 214 + 225? (a) 600 (b) 400 (c) 200
  8. 8.Best estimate of 51 × 16? (a) 100 (b) 10000 (c) 1000
  9. 9.Best estimate of 872 + 439? (a) 1100 (b) 1300 (c) 1500
  10. 10.Best estimate of 377 + 562? (a) 1200 (b) 1000 (c) 800
  11. 11.Best estimate of 413 + 451? (a) 700 (b) 1100 (c) 900
  12. 12.Best estimate of 17 × 22? (a) 400 (b) 4000 (c) 40
  13. 13.Best estimate of 39 × 46? (a) 20000 (b) 200 (c) 2000
  14. 14.Best estimate of 53 × 96? (a) 50000 (b) 500 (c) 5000
  15. 15.Best estimate of 207 + 176? (a) 400 (b) 200 (c) 600
  16. 16.Best estimate of 18 × 68? (a) 140 (b) 14000 (c) 1400
  17. 17.Best estimate of 601 + 576? (a) 1400 (b) 1200 (c) 1000
  18. 18.Best estimate of 627 + 705? (a) 1500 (b) 1100 (c) 1300
  19. 19.Best estimate of 769 + 627? (a) 1400 (b) 1600 (c) 1200
  20. 20.Best estimate of 29 × 17? (a) 6000 (b) 60 (c) 600
  21. 21.Best estimate of 28 × 44? (a) 12000 (b) 120 (c) 1200
  22. 22.Best estimate of 71 × 26? (a) 2100 (b) 21000 (c) 210
  23. 23.Best estimate of 395 + 425? (a) 800 (b) 600 (c) 1000
  24. 24.Best estimate of 48 × 13? (a) 5000 (b) 500 (c) 50
  25. 25.Best estimate of 310 + 244? (a) 500 (b) 700 (c) 300
  26. 26.Best estimate of 22 × 14? (a) 200 (b) 2000 (c) 20
  27. 27.Best estimate of 50 × 26? (a) 1500 (b) 150 (c) 15000
  28. 28.Best estimate of 63 × 68? (a) 42000 (b) 420 (c) 4200
  29. 29.Best estimate of 669 + 225? (a) 900 (b) 700 (c) 1100
  30. 30.Best estimate of 504 + 165? (a) 500 (b) 700 (c) 900
  31. 31.Best estimate of 68 × 66? (a) 4900 (b) 49000 (c) 490
  32. 32.Best estimate of 466 + 218? (a) 700 (b) 900 (c) 500
  33. 33.Best estimate of 781 + 675? (a) 1700 (b) 1500 (c) 1300
  34. 34.Best estimate of 240 + 337? (a) 700 (b) 300 (c) 500
  35. 35.Best estimate of 41 × 17? (a) 80 (b) 8000 (c) 800
  36. 36.Best estimate of 86 × 16? (a) 1800 (b) 18000 (c) 180
  37. 37.Best estimate of 878 + 269? (a) 1200 (b) 1400 (c) 1000
  38. 38.Best estimate of 810 + 607? (a) 1600 (b) 1400 (c) 1200
  39. 39.Best estimate of 472 + 453? (a) 1200 (b) 1000 (c) 800
  40. 40.Best estimate of 16 × 59? (a) 12000 (b) 120 (c) 1200

Answer key

  1. 3000
  2. 2000
  3. 1400
  4. 1000
  5. 1300
  6. 1000
  7. 400
  8. 1000
  9. 1300
  10. 1000
  11. 900
  12. 400
  13. 2000
  14. 5000
  15. 400
  16. 1400
  17. 1200
  18. 1300
  19. 1400
  20. 600
  21. 1200
  22. 2100
  23. 800
  24. 500
  25. 500
  26. 200
  27. 1500
  28. 4200
  29. 900
  30. 700
  31. 4900
  32. 700
  33. 1500
  34. 500
  35. 800
  36. 1800
  37. 1200
  38. 1400
  39. 1000
  40. 1200

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