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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 746 · 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 325 + 240? (a) 300 (b) 700 (c) 500
  2. 2.Best estimate of 73 × 43? (a) 280 (b) 28000 (c) 2800
  3. 3.Best estimate of 53 × 66? (a) 35000 (b) 3500 (c) 350
  4. 4.Best estimate of 832 + 326? (a) 1300 (b) 900 (c) 1100
  5. 5.Best estimate of 48 × 30? (a) 15000 (b) 1500 (c) 150
  6. 6.Best estimate of 84 × 58? (a) 48000 (b) 480 (c) 4800
  7. 7.Best estimate of 179 + 776? (a) 800 (b) 1000 (c) 1200
  8. 8.Best estimate of 313 + 734? (a) 800 (b) 1200 (c) 1000
  9. 9.Best estimate of 63 × 14? (a) 6000 (b) 600 (c) 60
  10. 10.Best estimate of 62 × 61? (a) 36000 (b) 3600 (c) 360
  11. 11.Best estimate of 91 × 69? (a) 63000 (b) 6300 (c) 630
  12. 12.Best estimate of 56 × 13? (a) 600 (b) 6000 (c) 60
  13. 13.Best estimate of 754 + 594? (a) 1400 (b) 1200 (c) 1600
  14. 14.Best estimate of 636 + 491? (a) 1300 (b) 900 (c) 1100
  15. 15.Best estimate of 205 + 248? (a) 200 (b) 600 (c) 400
  16. 16.Best estimate of 41 × 36? (a) 16000 (b) 1600 (c) 160
  17. 17.Best estimate of 440 + 593? (a) 1000 (b) 1200 (c) 800
  18. 18.Best estimate of 451 + 708? (a) 1400 (b) 1000 (c) 1200
  19. 19.Best estimate of 63 × 92? (a) 540 (b) 54000 (c) 5400
  20. 20.Best estimate of 870 + 671? (a) 1600 (b) 1800 (c) 1400
  21. 21.Best estimate of 862 + 241? (a) 1100 (b) 900 (c) 1300
  22. 22.Best estimate of 136 + 244? (a) 500 (b) 100 (c) 300
  23. 23.Best estimate of 530 + 548? (a) 1200 (b) 1000 (c) 800
  24. 24.Best estimate of 58 × 92? (a) 5400 (b) 540 (c) 54000
  25. 25.Best estimate of 649 + 639? (a) 1000 (b) 1400 (c) 1200
  26. 26.Best estimate of 49 × 83? (a) 4000 (b) 40000 (c) 400
  27. 27.Best estimate of 183 + 137? (a) 300 (b) 500 (c) 100
  28. 28.Best estimate of 137 + 175? (a) 100 (b) 300 (c) 500
  29. 29.Best estimate of 611 + 620? (a) 1400 (b) 1000 (c) 1200
  30. 30.Best estimate of 88 × 19? (a) 180 (b) 1800 (c) 18000
  31. 31.Best estimate of 78 × 23? (a) 160 (b) 16000 (c) 1600
  32. 32.Best estimate of 98 × 30? (a) 300 (b) 3000 (c) 30000
  33. 33.Best estimate of 17 × 92? (a) 180 (b) 1800 (c) 18000
  34. 34.Best estimate of 613 + 176? (a) 800 (b) 600 (c) 1000
  35. 35.Best estimate of 157 + 497? (a) 700 (b) 500 (c) 900
  36. 36.Best estimate of 671 + 837? (a) 1700 (b) 1300 (c) 1500
  37. 37.Best estimate of 295 + 318? (a) 800 (b) 600 (c) 400
  38. 38.Best estimate of 26 × 26? (a) 900 (b) 90 (c) 9000
  39. 39.Best estimate of 534 + 546? (a) 1200 (b) 800 (c) 1000
  40. 40.Best estimate of 52 × 24? (a) 10000 (b) 100 (c) 1000

Answer key

  1. 500
  2. 2800
  3. 3500
  4. 1100
  5. 1500
  6. 4800
  7. 1000
  8. 1000
  9. 600
  10. 3600
  11. 6300
  12. 600
  13. 1400
  14. 1100
  15. 400
  16. 1600
  17. 1000
  18. 1200
  19. 5400
  20. 1600
  21. 1100
  22. 300
  23. 1000
  24. 5400
  25. 1200
  26. 4000
  27. 300
  28. 300
  29. 1200
  30. 1800
  31. 1600
  32. 3000
  33. 1800
  34. 800
  35. 700
  36. 1500
  37. 600
  38. 900
  39. 1000
  40. 1000

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