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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 513 · 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 56 × 66? (a) 420 (b) 42000 (c) 4200
  2. 2.Best estimate of 79 × 87? (a) 7200 (b) 72000 (c) 720
  3. 3.Best estimate of 76 × 38? (a) 320 (b) 3200 (c) 32000
  4. 4.Best estimate of 30 × 60? (a) 1800 (b) 180 (c) 18000
  5. 5.Best estimate of 57 × 76? (a) 480 (b) 48000 (c) 4800
  6. 6.Best estimate of 23 × 34? (a) 600 (b) 6000 (c) 60
  7. 7.Best estimate of 89 × 52? (a) 45000 (b) 450 (c) 4500
  8. 8.Best estimate of 53 × 87? (a) 45000 (b) 4500 (c) 450
  9. 9.Best estimate of 526 + 244? (a) 700 (b) 500 (c) 900
  10. 10.Best estimate of 498 + 475? (a) 800 (b) 1200 (c) 1000
  11. 11.Best estimate of 31 × 82? (a) 2400 (b) 240 (c) 24000
  12. 12.Best estimate of 452 + 799? (a) 1300 (b) 1100 (c) 1500
  13. 13.Best estimate of 42 × 32? (a) 120 (b) 12000 (c) 1200
  14. 14.Best estimate of 98 × 56? (a) 60000 (b) 6000 (c) 600
  15. 15.Best estimate of 154 + 484? (a) 700 (b) 500 (c) 900
  16. 16.Best estimate of 26 × 36? (a) 12000 (b) 120 (c) 1200
  17. 17.Best estimate of 80 × 86? (a) 720 (b) 7200 (c) 72000
  18. 18.Best estimate of 439 + 835? (a) 1400 (b) 1200 (c) 1000
  19. 19.Best estimate of 16 × 23? (a) 40 (b) 4000 (c) 400
  20. 20.Best estimate of 74 × 86? (a) 630 (b) 6300 (c) 63000
  21. 21.Best estimate of 47 × 66? (a) 35000 (b) 3500 (c) 350
  22. 22.Best estimate of 56 × 96? (a) 60000 (b) 6000 (c) 600
  23. 23.Best estimate of 91 × 61? (a) 540 (b) 5400 (c) 54000
  24. 24.Best estimate of 859 + 188? (a) 900 (b) 1300 (c) 1100
  25. 25.Best estimate of 40 × 82? (a) 3200 (b) 320 (c) 32000
  26. 26.Best estimate of 30 × 19? (a) 6000 (b) 60 (c) 600
  27. 27.Best estimate of 528 + 651? (a) 1000 (b) 1200 (c) 1400
  28. 28.Best estimate of 92 × 81? (a) 7200 (b) 72000 (c) 720
  29. 29.Best estimate of 317 + 323? (a) 800 (b) 600 (c) 400
  30. 30.Best estimate of 247 + 520? (a) 900 (b) 500 (c) 700
  31. 31.Best estimate of 33 × 71? (a) 21000 (b) 2100 (c) 210
  32. 32.Best estimate of 539 + 258? (a) 600 (b) 800 (c) 1000
  33. 33.Best estimate of 31 × 64? (a) 18000 (b) 1800 (c) 180
  34. 34.Best estimate of 76 × 22? (a) 16000 (b) 1600 (c) 160
  35. 35.Best estimate of 125 + 630? (a) 700 (b) 900 (c) 500
  36. 36.Best estimate of 18 × 52? (a) 100 (b) 1000 (c) 10000
  37. 37.Best estimate of 634 + 875? (a) 1500 (b) 1300 (c) 1700
  38. 38.Best estimate of 14 × 66? (a) 70 (b) 700 (c) 7000
  39. 39.Best estimate of 84 × 39? (a) 320 (b) 3200 (c) 32000
  40. 40.Best estimate of 80 × 38? (a) 320 (b) 32000 (c) 3200

Answer key

  1. 4200
  2. 7200
  3. 3200
  4. 1800
  5. 4800
  6. 600
  7. 4500
  8. 4500
  9. 700
  10. 1000
  11. 2400
  12. 1300
  13. 1200
  14. 6000
  15. 700
  16. 1200
  17. 7200
  18. 1200
  19. 400
  20. 6300
  21. 3500
  22. 6000
  23. 5400
  24. 1100
  25. 3200
  26. 600
  27. 1200
  28. 7200
  29. 600
  30. 700
  31. 2100
  32. 800
  33. 1800
  34. 1600
  35. 700
  36. 1000
  37. 1500
  38. 700
  39. 3200
  40. 3200

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