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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 481 · 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 64 × 33? (a) 18000 (b) 180 (c) 1800
  2. 2.Best estimate of 13 × 56? (a) 60 (b) 600 (c) 6000
  3. 3.Best estimate of 569 + 208? (a) 600 (b) 1000 (c) 800
  4. 4.Best estimate of 619 + 579? (a) 1000 (b) 1200 (c) 1400
  5. 5.Best estimate of 38 × 76? (a) 3200 (b) 320 (c) 32000
  6. 6.Best estimate of 600 + 561? (a) 1400 (b) 1000 (c) 1200
  7. 7.Best estimate of 87 × 72? (a) 6300 (b) 63000 (c) 630
  8. 8.Best estimate of 37 × 73? (a) 2800 (b) 28000 (c) 280
  9. 9.Best estimate of 48 × 17? (a) 1000 (b) 10000 (c) 100
  10. 10.Best estimate of 395 + 656? (a) 900 (b) 1100 (c) 1300
  11. 11.Best estimate of 840 + 692? (a) 1700 (b) 1500 (c) 1300
  12. 12.Best estimate of 29 × 79? (a) 2400 (b) 240 (c) 24000
  13. 13.Best estimate of 406 + 437? (a) 1000 (b) 600 (c) 800
  14. 14.Best estimate of 91 × 83? (a) 72000 (b) 7200 (c) 720
  15. 15.Best estimate of 33 × 31? (a) 900 (b) 9000 (c) 90
  16. 16.Best estimate of 48 × 97? (a) 5000 (b) 50000 (c) 500
  17. 17.Best estimate of 843 + 534? (a) 1300 (b) 1500 (c) 1100
  18. 18.Best estimate of 655 + 727? (a) 1600 (b) 1200 (c) 1400
  19. 19.Best estimate of 542 + 398? (a) 900 (b) 700 (c) 1100
  20. 20.Best estimate of 24 × 81? (a) 16000 (b) 160 (c) 1600
  21. 21.Best estimate of 604 + 737? (a) 1100 (b) 1300 (c) 1500
  22. 22.Best estimate of 289 + 290? (a) 800 (b) 400 (c) 600
  23. 23.Best estimate of 864 + 506? (a) 1200 (b) 1400 (c) 1600
  24. 24.Best estimate of 547 + 842? (a) 1500 (b) 1300 (c) 1100
  25. 25.Best estimate of 50 × 98? (a) 5000 (b) 50000 (c) 500
  26. 26.Best estimate of 813 + 763? (a) 1400 (b) 1800 (c) 1600
  27. 27.Best estimate of 199 + 441? (a) 800 (b) 600 (c) 400
  28. 28.Best estimate of 46 × 32? (a) 1500 (b) 150 (c) 15000
  29. 29.Best estimate of 368 + 448? (a) 800 (b) 600 (c) 1000
  30. 30.Best estimate of 16 × 72? (a) 14000 (b) 140 (c) 1400
  31. 31.Best estimate of 56 × 61? (a) 36000 (b) 3600 (c) 360
  32. 32.Best estimate of 555 + 569? (a) 1000 (b) 1200 (c) 1400
  33. 33.Best estimate of 66 × 88? (a) 6300 (b) 63000 (c) 630
  34. 34.Best estimate of 542 + 133? (a) 800 (b) 600 (c) 400
  35. 35.Best estimate of 14 × 97? (a) 10000 (b) 100 (c) 1000
  36. 36.Best estimate of 32 × 93? (a) 270 (b) 27000 (c) 2700
  37. 37.Best estimate of 77 × 16? (a) 160 (b) 16000 (c) 1600
  38. 38.Best estimate of 26 × 47? (a) 15000 (b) 150 (c) 1500
  39. 39.Best estimate of 357 + 405? (a) 600 (b) 1000 (c) 800
  40. 40.Best estimate of 97 × 98? (a) 1000 (b) 100000 (c) 10000

Answer key

  1. 1800
  2. 600
  3. 800
  4. 1200
  5. 3200
  6. 1200
  7. 6300
  8. 2800
  9. 1000
  10. 1100
  11. 1500
  12. 2400
  13. 800
  14. 7200
  15. 900
  16. 5000
  17. 1300
  18. 1400
  19. 900
  20. 1600
  21. 1300
  22. 600
  23. 1400
  24. 1300
  25. 5000
  26. 1600
  27. 600
  28. 1500
  29. 800
  30. 1400
  31. 3600
  32. 1200
  33. 6300
  34. 600
  35. 1000
  36. 2700
  37. 1600
  38. 1500
  39. 800
  40. 10000

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