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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 595 · 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 69 × 22? (a) 1400 (b) 140 (c) 14000
  2. 2.Best estimate of 92 × 97? (a) 9000 (b) 90000 (c) 900
  3. 3.Best estimate of 664 + 659? (a) 1600 (b) 1200 (c) 1400
  4. 4.Best estimate of 13 × 39? (a) 40 (b) 4000 (c) 400
  5. 5.Best estimate of 60 × 53? (a) 3000 (b) 30000 (c) 300
  6. 6.Best estimate of 144 + 143? (a) 400 (b) 0 (c) 200
  7. 7.Best estimate of 190 + 592? (a) 1000 (b) 600 (c) 800
  8. 8.Best estimate of 826 + 806? (a) 1400 (b) 1600 (c) 1800
  9. 9.Best estimate of 779 + 148? (a) 900 (b) 700 (c) 1100
  10. 10.Best estimate of 72 × 82? (a) 56000 (b) 560 (c) 5600
  11. 11.Best estimate of 36 × 86? (a) 36000 (b) 360 (c) 3600
  12. 12.Best estimate of 835 + 232? (a) 1000 (b) 800 (c) 1200
  13. 13.Best estimate of 416 + 424? (a) 600 (b) 1000 (c) 800
  14. 14.Best estimate of 87 × 72? (a) 630 (b) 63000 (c) 6300
  15. 15.Best estimate of 880 + 693? (a) 1800 (b) 1400 (c) 1600
  16. 16.Best estimate of 58 × 68? (a) 4200 (b) 420 (c) 42000
  17. 17.Best estimate of 77 × 14? (a) 800 (b) 80 (c) 8000
  18. 18.Best estimate of 225 + 329? (a) 700 (b) 500 (c) 300
  19. 19.Best estimate of 81 × 90? (a) 72000 (b) 720 (c) 7200
  20. 20.Best estimate of 472 + 876? (a) 1200 (b) 1400 (c) 1600
  21. 21.Best estimate of 66 × 87? (a) 63000 (b) 6300 (c) 630
  22. 22.Best estimate of 411 + 474? (a) 1100 (b) 900 (c) 700
  23. 23.Best estimate of 16 × 36? (a) 800 (b) 8000 (c) 80
  24. 24.Best estimate of 22 × 94? (a) 18000 (b) 1800 (c) 180
  25. 25.Best estimate of 70 × 88? (a) 6300 (b) 63000 (c) 630
  26. 26.Best estimate of 41 × 36? (a) 16000 (b) 160 (c) 1600
  27. 27.Best estimate of 14 × 54? (a) 500 (b) 5000 (c) 50
  28. 28.Best estimate of 23 × 66? (a) 140 (b) 14000 (c) 1400
  29. 29.Best estimate of 52 × 59? (a) 300 (b) 3000 (c) 30000
  30. 30.Best estimate of 773 + 167? (a) 800 (b) 1200 (c) 1000
  31. 31.Best estimate of 52 × 76? (a) 400 (b) 4000 (c) 40000
  32. 32.Best estimate of 86 × 74? (a) 63000 (b) 6300 (c) 630
  33. 33.Best estimate of 16 × 43? (a) 80 (b) 8000 (c) 800
  34. 34.Best estimate of 53 × 70? (a) 350 (b) 3500 (c) 35000
  35. 35.Best estimate of 238 + 264? (a) 300 (b) 700 (c) 500
  36. 36.Best estimate of 68 × 78? (a) 560 (b) 5600 (c) 56000
  37. 37.Best estimate of 51 × 13? (a) 5000 (b) 50 (c) 500
  38. 38.Best estimate of 41 × 83? (a) 320 (b) 32000 (c) 3200
  39. 39.Best estimate of 237 + 452? (a) 700 (b) 500 (c) 900
  40. 40.Best estimate of 16 × 39? (a) 800 (b) 80 (c) 8000

Answer key

  1. 1400
  2. 9000
  3. 1400
  4. 400
  5. 3000
  6. 200
  7. 800
  8. 1600
  9. 900
  10. 5600
  11. 3600
  12. 1000
  13. 800
  14. 6300
  15. 1600
  16. 4200
  17. 800
  18. 500
  19. 7200
  20. 1400
  21. 6300
  22. 900
  23. 800
  24. 1800
  25. 6300
  26. 1600
  27. 500
  28. 1400
  29. 3000
  30. 1000
  31. 4000
  32. 6300
  33. 800
  34. 3500
  35. 500
  36. 5600
  37. 500
  38. 3200
  39. 700
  40. 800

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