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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 182 · 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 66 × 12? (a) 7000 (b) 70 (c) 700
  2. 2.Best estimate of 734 + 778? (a) 1300 (b) 1700 (c) 1500
  3. 3.Best estimate of 143 + 454? (a) 800 (b) 400 (c) 600
  4. 4.Best estimate of 42 × 56? (a) 240 (b) 2400 (c) 24000
  5. 5.Best estimate of 97 × 36? (a) 40000 (b) 4000 (c) 400
  6. 6.Best estimate of 68 × 96? (a) 700 (b) 7000 (c) 70000
  7. 7.Best estimate of 36 × 83? (a) 3200 (b) 320 (c) 32000
  8. 8.Best estimate of 36 × 59? (a) 240 (b) 2400 (c) 24000
  9. 9.Best estimate of 81 × 66? (a) 5600 (b) 56000 (c) 560
  10. 10.Best estimate of 231 + 595? (a) 800 (b) 1000 (c) 600
  11. 11.Best estimate of 306 + 845? (a) 1300 (b) 1100 (c) 900
  12. 12.Best estimate of 82 × 36? (a) 32000 (b) 3200 (c) 320
  13. 13.Best estimate of 17 × 13? (a) 200 (b) 2000 (c) 20
  14. 14.Best estimate of 567 + 473? (a) 1100 (b) 1300 (c) 900
  15. 15.Best estimate of 538 + 645? (a) 1300 (b) 1100 (c) 900
  16. 16.Best estimate of 32 × 39? (a) 120 (b) 12000 (c) 1200
  17. 17.Best estimate of 284 + 685? (a) 800 (b) 1000 (c) 1200
  18. 18.Best estimate of 802 + 655? (a) 1700 (b) 1300 (c) 1500
  19. 19.Best estimate of 98 × 89? (a) 90000 (b) 900 (c) 9000
  20. 20.Best estimate of 618 + 447? (a) 1200 (b) 1000 (c) 800
  21. 21.Best estimate of 66 × 24? (a) 140 (b) 14000 (c) 1400
  22. 22.Best estimate of 196 + 878? (a) 1100 (b) 1300 (c) 900
  23. 23.Best estimate of 484 + 703? (a) 1000 (b) 1200 (c) 1400
  24. 24.Best estimate of 792 + 756? (a) 1800 (b) 1400 (c) 1600
  25. 25.Best estimate of 69 × 62? (a) 4200 (b) 42000 (c) 420
  26. 26.Best estimate of 62 × 54? (a) 30000 (b) 3000 (c) 300
  27. 27.Best estimate of 86 × 66? (a) 630 (b) 63000 (c) 6300
  28. 28.Best estimate of 871 + 681? (a) 1800 (b) 1600 (c) 1400
  29. 29.Best estimate of 416 + 202? (a) 400 (b) 600 (c) 800
  30. 30.Best estimate of 488 + 280? (a) 1000 (b) 600 (c) 800
  31. 31.Best estimate of 688 + 655? (a) 1200 (b) 1600 (c) 1400
  32. 32.Best estimate of 58 × 78? (a) 4800 (b) 48000 (c) 480
  33. 33.Best estimate of 325 + 215? (a) 300 (b) 500 (c) 700
  34. 34.Best estimate of 225 + 659? (a) 900 (b) 700 (c) 1100
  35. 35.Best estimate of 74 × 72? (a) 4900 (b) 49000 (c) 490
  36. 36.Best estimate of 32 × 48? (a) 15000 (b) 1500 (c) 150
  37. 37.Best estimate of 516 + 391? (a) 900 (b) 1100 (c) 700
  38. 38.Best estimate of 96 × 26? (a) 3000 (b) 30000 (c) 300
  39. 39.Best estimate of 457 + 585? (a) 1300 (b) 1100 (c) 900
  40. 40.Best estimate of 640 + 166? (a) 800 (b) 600 (c) 1000

Answer key

  1. 700
  2. 1500
  3. 600
  4. 2400
  5. 4000
  6. 7000
  7. 3200
  8. 2400
  9. 5600
  10. 800
  11. 1100
  12. 3200
  13. 200
  14. 1100
  15. 1100
  16. 1200
  17. 1000
  18. 1500
  19. 9000
  20. 1000
  21. 1400
  22. 1100
  23. 1200
  24. 1600
  25. 4200
  26. 3000
  27. 6300
  28. 1600
  29. 600
  30. 800
  31. 1400
  32. 4800
  33. 500
  34. 900
  35. 4900
  36. 1500
  37. 900
  38. 3000
  39. 1100
  40. 800

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