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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 601 · 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 83 × 90? (a) 7200 (b) 72000 (c) 720
  2. 2.Best estimate of 50 × 41? (a) 20000 (b) 2000 (c) 200
  3. 3.Best estimate of 56 × 87? (a) 5400 (b) 54000 (c) 540
  4. 4.Best estimate of 21 × 68? (a) 140 (b) 14000 (c) 1400
  5. 5.Best estimate of 412 + 655? (a) 1300 (b) 900 (c) 1100
  6. 6.Best estimate of 94 × 26? (a) 270 (b) 2700 (c) 27000
  7. 7.Best estimate of 88 × 36? (a) 360 (b) 36000 (c) 3600
  8. 8.Best estimate of 18 × 69? (a) 14000 (b) 1400 (c) 140
  9. 9.Best estimate of 346 + 639? (a) 700 (b) 1100 (c) 900
  10. 10.Best estimate of 797 + 811? (a) 1600 (b) 1400 (c) 1800
  11. 11.Best estimate of 26 × 16? (a) 600 (b) 60 (c) 6000
  12. 12.Best estimate of 66 × 36? (a) 2800 (b) 28000 (c) 280
  13. 13.Best estimate of 231 + 504? (a) 500 (b) 900 (c) 700
  14. 14.Best estimate of 443 + 764? (a) 1400 (b) 1200 (c) 1000
  15. 15.Best estimate of 356 + 592? (a) 1200 (b) 1000 (c) 800
  16. 16.Best estimate of 87 × 46? (a) 45000 (b) 4500 (c) 450
  17. 17.Best estimate of 743 + 332? (a) 1000 (b) 1200 (c) 800
  18. 18.Best estimate of 76 × 57? (a) 48000 (b) 4800 (c) 480
  19. 19.Best estimate of 16 × 96? (a) 200 (b) 2000 (c) 20000
  20. 20.Best estimate of 312 + 597? (a) 1100 (b) 700 (c) 900
  21. 21.Best estimate of 764 + 761? (a) 1600 (b) 1800 (c) 1400
  22. 22.Best estimate of 66 × 59? (a) 42000 (b) 420 (c) 4200
  23. 23.Best estimate of 598 + 567? (a) 1000 (b) 1400 (c) 1200
  24. 24.Best estimate of 24 × 17? (a) 40 (b) 4000 (c) 400
  25. 25.Best estimate of 434 + 132? (a) 500 (b) 700 (c) 300
  26. 26.Best estimate of 52 × 47? (a) 2500 (b) 25000 (c) 250
  27. 27.Best estimate of 718 + 443? (a) 1300 (b) 1100 (c) 900
  28. 28.Best estimate of 381 + 596? (a) 1000 (b) 1200 (c) 800
  29. 29.Best estimate of 93 × 52? (a) 4500 (b) 45000 (c) 450
  30. 30.Best estimate of 582 + 712? (a) 1500 (b) 1100 (c) 1300
  31. 31.Best estimate of 69 × 18? (a) 1400 (b) 14000 (c) 140
  32. 32.Best estimate of 391 + 599? (a) 800 (b) 1000 (c) 1200
  33. 33.Best estimate of 19 × 28? (a) 6000 (b) 60 (c) 600
  34. 34.Best estimate of 682 + 198? (a) 1100 (b) 700 (c) 900
  35. 35.Best estimate of 266 + 256? (a) 600 (b) 800 (c) 400
  36. 36.Best estimate of 93 × 22? (a) 1800 (b) 180 (c) 18000
  37. 37.Best estimate of 516 + 567? (a) 900 (b) 1300 (c) 1100
  38. 38.Best estimate of 41 × 83? (a) 32000 (b) 3200 (c) 320
  39. 39.Best estimate of 76 × 52? (a) 40000 (b) 400 (c) 4000
  40. 40.Best estimate of 560 + 821? (a) 1200 (b) 1400 (c) 1600

Answer key

  1. 7200
  2. 2000
  3. 5400
  4. 1400
  5. 1100
  6. 2700
  7. 3600
  8. 1400
  9. 900
  10. 1600
  11. 600
  12. 2800
  13. 700
  14. 1200
  15. 1000
  16. 4500
  17. 1000
  18. 4800
  19. 2000
  20. 900
  21. 1600
  22. 4200
  23. 1200
  24. 400
  25. 500
  26. 2500
  27. 1100
  28. 1000
  29. 4500
  30. 1300
  31. 1400
  32. 1000
  33. 600
  34. 900
  35. 600
  36. 1800
  37. 1100
  38. 3200
  39. 4000
  40. 1400

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