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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 73 · 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 53 × 69? (a) 35000 (b) 3500 (c) 350
  2. 2.Best estimate of 627 + 470? (a) 900 (b) 1300 (c) 1100
  3. 3.Best estimate of 58 × 73? (a) 4200 (b) 420 (c) 42000
  4. 4.Best estimate of 68 × 76? (a) 56000 (b) 5600 (c) 560
  5. 5.Best estimate of 14 × 57? (a) 6000 (b) 60 (c) 600
  6. 6.Best estimate of 445 + 293? (a) 700 (b) 500 (c) 900
  7. 7.Best estimate of 699 + 544? (a) 1000 (b) 1400 (c) 1200
  8. 8.Best estimate of 745 + 584? (a) 1100 (b) 1300 (c) 1500
  9. 9.Best estimate of 366 + 333? (a) 500 (b) 700 (c) 900
  10. 10.Best estimate of 30 × 36? (a) 120 (b) 1200 (c) 12000
  11. 11.Best estimate of 56 × 57? (a) 3600 (b) 360 (c) 36000
  12. 12.Best estimate of 46 × 13? (a) 5000 (b) 500 (c) 50
  13. 13.Best estimate of 67 × 39? (a) 2800 (b) 280 (c) 28000
  14. 14.Best estimate of 67 × 56? (a) 42000 (b) 420 (c) 4200
  15. 15.Best estimate of 804 + 805? (a) 1400 (b) 1800 (c) 1600
  16. 16.Best estimate of 96 × 76? (a) 80000 (b) 8000 (c) 800
  17. 17.Best estimate of 769 + 480? (a) 1300 (b) 1100 (c) 1500
  18. 18.Best estimate of 22 × 23? (a) 40 (b) 4000 (c) 400
  19. 19.Best estimate of 641 + 560? (a) 1400 (b) 1000 (c) 1200
  20. 20.Best estimate of 668 + 556? (a) 1300 (b) 1500 (c) 1100
  21. 21.Best estimate of 343 + 413? (a) 900 (b) 700 (c) 500
  22. 22.Best estimate of 342 + 336? (a) 800 (b) 400 (c) 600
  23. 23.Best estimate of 81 × 92? (a) 72000 (b) 7200 (c) 720
  24. 24.Best estimate of 67 × 19? (a) 1400 (b) 14000 (c) 140
  25. 25.Best estimate of 13 × 17? (a) 20 (b) 200 (c) 2000
  26. 26.Best estimate of 36 × 48? (a) 2000 (b) 200 (c) 20000
  27. 27.Best estimate of 72 × 68? (a) 4900 (b) 49000 (c) 490
  28. 28.Best estimate of 197 + 121? (a) 300 (b) 100 (c) 500
  29. 29.Best estimate of 49 × 43? (a) 2000 (b) 200 (c) 20000
  30. 30.Best estimate of 12 × 60? (a) 600 (b) 60 (c) 6000
  31. 31.Best estimate of 68 × 31? (a) 2100 (b) 21000 (c) 210
  32. 32.Best estimate of 413 + 619? (a) 1200 (b) 1000 (c) 800
  33. 33.Best estimate of 671 + 705? (a) 1400 (b) 1600 (c) 1200
  34. 34.Best estimate of 67 × 23? (a) 140 (b) 14000 (c) 1400
  35. 35.Best estimate of 481 + 719? (a) 1400 (b) 1000 (c) 1200
  36. 36.Best estimate of 348 + 545? (a) 600 (b) 800 (c) 1000
  37. 37.Best estimate of 851 + 209? (a) 1300 (b) 900 (c) 1100
  38. 38.Best estimate of 93 × 73? (a) 630 (b) 63000 (c) 6300
  39. 39.Best estimate of 658 + 266? (a) 1200 (b) 800 (c) 1000
  40. 40.Best estimate of 26 × 69? (a) 2100 (b) 21000 (c) 210

Answer key

  1. 3500
  2. 1100
  3. 4200
  4. 5600
  5. 600
  6. 700
  7. 1200
  8. 1300
  9. 700
  10. 1200
  11. 3600
  12. 500
  13. 2800
  14. 4200
  15. 1600
  16. 8000
  17. 1300
  18. 400
  19. 1200
  20. 1300
  21. 700
  22. 600
  23. 7200
  24. 1400
  25. 200
  26. 2000
  27. 4900
  28. 300
  29. 2000
  30. 600
  31. 2100
  32. 1000
  33. 1400
  34. 1400
  35. 1200
  36. 800
  37. 1100
  38. 6300
  39. 1000
  40. 2100

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