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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 814 · 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 67 × 52? (a) 35000 (b) 350 (c) 3500
  2. 2.Best estimate of 89 × 43? (a) 3600 (b) 36000 (c) 360
  3. 3.Best estimate of 248 + 846? (a) 800 (b) 1200 (c) 1000
  4. 4.Best estimate of 46 × 41? (a) 2000 (b) 200 (c) 20000
  5. 5.Best estimate of 457 + 508? (a) 1200 (b) 800 (c) 1000
  6. 6.Best estimate of 22 × 58? (a) 12000 (b) 1200 (c) 120
  7. 7.Best estimate of 16 × 34? (a) 60 (b) 600 (c) 6000
  8. 8.Best estimate of 837 + 836? (a) 1800 (b) 1400 (c) 1600
  9. 9.Best estimate of 148 + 331? (a) 600 (b) 400 (c) 200
  10. 10.Best estimate of 82 × 64? (a) 480 (b) 4800 (c) 48000
  11. 11.Best estimate of 40 × 20? (a) 800 (b) 8000 (c) 80
  12. 12.Best estimate of 686 + 183? (a) 700 (b) 900 (c) 1100
  13. 13.Best estimate of 29 × 93? (a) 270 (b) 2700 (c) 27000
  14. 14.Best estimate of 215 + 629? (a) 800 (b) 1000 (c) 600
  15. 15.Best estimate of 749 + 259? (a) 1000 (b) 800 (c) 1200
  16. 16.Best estimate of 31 × 27? (a) 90 (b) 900 (c) 9000
  17. 17.Best estimate of 84 × 83? (a) 6400 (b) 640 (c) 64000
  18. 18.Best estimate of 429 + 422? (a) 1000 (b) 800 (c) 600
  19. 19.Best estimate of 33 × 62? (a) 1800 (b) 18000 (c) 180
  20. 20.Best estimate of 79 × 78? (a) 64000 (b) 640 (c) 6400
  21. 21.Best estimate of 222 + 778? (a) 1200 (b) 800 (c) 1000
  22. 22.Best estimate of 87 × 21? (a) 1800 (b) 180 (c) 18000
  23. 23.Best estimate of 552 + 576? (a) 1400 (b) 1200 (c) 1000
  24. 24.Best estimate of 303 + 598? (a) 700 (b) 900 (c) 1100
  25. 25.Best estimate of 516 + 181? (a) 700 (b) 900 (c) 500
  26. 26.Best estimate of 64 × 21? (a) 120 (b) 12000 (c) 1200
  27. 27.Best estimate of 67 × 90? (a) 63000 (b) 6300 (c) 630
  28. 28.Best estimate of 60 × 79? (a) 48000 (b) 480 (c) 4800
  29. 29.Best estimate of 43 × 33? (a) 120 (b) 1200 (c) 12000
  30. 30.Best estimate of 89 × 58? (a) 5400 (b) 54000 (c) 540
  31. 31.Best estimate of 86 × 78? (a) 7200 (b) 720 (c) 72000
  32. 32.Best estimate of 26 × 86? (a) 27000 (b) 270 (c) 2700
  33. 33.Best estimate of 762 + 281? (a) 900 (b) 1300 (c) 1100
  34. 34.Best estimate of 546 + 513? (a) 1200 (b) 1000 (c) 800
  35. 35.Best estimate of 562 + 614? (a) 1200 (b) 1400 (c) 1000
  36. 36.Best estimate of 654 + 160? (a) 1100 (b) 700 (c) 900
  37. 37.Best estimate of 26 × 19? (a) 6000 (b) 600 (c) 60
  38. 38.Best estimate of 16 × 19? (a) 40 (b) 4000 (c) 400
  39. 39.Best estimate of 445 + 487? (a) 1100 (b) 900 (c) 700
  40. 40.Best estimate of 27 × 72? (a) 2100 (b) 21000 (c) 210

Answer key

  1. 3500
  2. 3600
  3. 1000
  4. 2000
  5. 1000
  6. 1200
  7. 600
  8. 1600
  9. 400
  10. 4800
  11. 800
  12. 900
  13. 2700
  14. 800
  15. 1000
  16. 900
  17. 6400
  18. 800
  19. 1800
  20. 6400
  21. 1000
  22. 1800
  23. 1200
  24. 900
  25. 700
  26. 1200
  27. 6300
  28. 4800
  29. 1200
  30. 5400
  31. 7200
  32. 2700
  33. 1100
  34. 1000
  35. 1200
  36. 900
  37. 600
  38. 400
  39. 900
  40. 2100

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