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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 903 · 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 145 + 508? (a) 600 (b) 400 (c) 800
  2. 2.Best estimate of 851 + 343? (a) 1400 (b) 1200 (c) 1000
  3. 3.Best estimate of 720 + 724? (a) 1200 (b) 1600 (c) 1400
  4. 4.Best estimate of 606 + 610? (a) 1200 (b) 1400 (c) 1000
  5. 5.Best estimate of 94 × 82? (a) 7200 (b) 720 (c) 72000
  6. 6.Best estimate of 14 × 24? (a) 2000 (b) 200 (c) 20
  7. 7.Best estimate of 30 × 93? (a) 27000 (b) 270 (c) 2700
  8. 8.Best estimate of 84 × 30? (a) 24000 (b) 2400 (c) 240
  9. 9.Best estimate of 92 × 66? (a) 6300 (b) 630 (c) 63000
  10. 10.Best estimate of 278 + 247? (a) 700 (b) 300 (c) 500
  11. 11.Best estimate of 620 + 141? (a) 900 (b) 500 (c) 700
  12. 12.Best estimate of 60 × 31? (a) 1800 (b) 18000 (c) 180
  13. 13.Best estimate of 198 + 169? (a) 400 (b) 600 (c) 200
  14. 14.Best estimate of 313 + 199? (a) 300 (b) 500 (c) 700
  15. 15.Best estimate of 763 + 843? (a) 1800 (b) 1400 (c) 1600
  16. 16.Best estimate of 734 + 133? (a) 600 (b) 1000 (c) 800
  17. 17.Best estimate of 27 × 91? (a) 2700 (b) 27000 (c) 270
  18. 18.Best estimate of 244 + 841? (a) 1000 (b) 1200 (c) 800
  19. 19.Best estimate of 749 + 815? (a) 1500 (b) 1700 (c) 1300
  20. 20.Best estimate of 652 + 195? (a) 900 (b) 700 (c) 1100
  21. 21.Best estimate of 97 × 57? (a) 600 (b) 6000 (c) 60000
  22. 22.Best estimate of 68 × 66? (a) 4900 (b) 490 (c) 49000
  23. 23.Best estimate of 768 + 451? (a) 1500 (b) 1100 (c) 1300
  24. 24.Best estimate of 34 × 47? (a) 150 (b) 1500 (c) 15000
  25. 25.Best estimate of 769 + 492? (a) 1500 (b) 1300 (c) 1100
  26. 26.Best estimate of 186 + 346? (a) 500 (b) 700 (c) 300
  27. 27.Best estimate of 16 × 90? (a) 18000 (b) 180 (c) 1800
  28. 28.Best estimate of 79 × 71? (a) 5600 (b) 56000 (c) 560
  29. 29.Best estimate of 70 × 39? (a) 28000 (b) 280 (c) 2800
  30. 30.Best estimate of 58 × 49? (a) 300 (b) 3000 (c) 30000
  31. 31.Best estimate of 92 × 40? (a) 3600 (b) 360 (c) 36000
  32. 32.Best estimate of 56 × 24? (a) 1200 (b) 12000 (c) 120
  33. 33.Best estimate of 383 + 536? (a) 1100 (b) 700 (c) 900
  34. 34.Best estimate of 72 × 71? (a) 4900 (b) 49000 (c) 490
  35. 35.Best estimate of 63 × 36? (a) 24000 (b) 2400 (c) 240
  36. 36.Best estimate of 839 + 810? (a) 1600 (b) 1800 (c) 1400
  37. 37.Best estimate of 76 × 90? (a) 7200 (b) 720 (c) 72000
  38. 38.Best estimate of 24 × 27? (a) 6000 (b) 60 (c) 600
  39. 39.Best estimate of 663 + 512? (a) 1200 (b) 1000 (c) 1400
  40. 40.Best estimate of 79 × 26? (a) 24000 (b) 2400 (c) 240

Answer key

  1. 600
  2. 1200
  3. 1400
  4. 1200
  5. 7200
  6. 200
  7. 2700
  8. 2400
  9. 6300
  10. 500
  11. 700
  12. 1800
  13. 400
  14. 500
  15. 1600
  16. 800
  17. 2700
  18. 1000
  19. 1500
  20. 900
  21. 6000
  22. 4900
  23. 1300
  24. 1500
  25. 1300
  26. 500
  27. 1800
  28. 5600
  29. 2800
  30. 3000
  31. 3600
  32. 1200
  33. 900
  34. 4900
  35. 2400
  36. 1600
  37. 7200
  38. 600
  39. 1200
  40. 2400

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