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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 892 · 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 90 × 62? (a) 5400 (b) 540 (c) 54000
  2. 2.Best estimate of 769 + 284? (a) 1100 (b) 900 (c) 1300
  3. 3.Best estimate of 675 + 384? (a) 900 (b) 1100 (c) 1300
  4. 4.Best estimate of 230 + 428? (a) 400 (b) 600 (c) 800
  5. 5.Best estimate of 49 × 53? (a) 2500 (b) 250 (c) 25000
  6. 6.Best estimate of 681 + 203? (a) 1100 (b) 700 (c) 900
  7. 7.Best estimate of 487 + 186? (a) 500 (b) 900 (c) 700
  8. 8.Best estimate of 827 + 198? (a) 800 (b) 1000 (c) 1200
  9. 9.Best estimate of 27 × 59? (a) 1800 (b) 180 (c) 18000
  10. 10.Best estimate of 43 × 42? (a) 160 (b) 1600 (c) 16000
  11. 11.Best estimate of 522 + 751? (a) 1500 (b) 1300 (c) 1100
  12. 12.Best estimate of 50 × 49? (a) 25000 (b) 2500 (c) 250
  13. 13.Best estimate of 46 × 39? (a) 2000 (b) 20000 (c) 200
  14. 14.Best estimate of 98 × 26? (a) 3000 (b) 30000 (c) 300
  15. 15.Best estimate of 76 × 80? (a) 64000 (b) 6400 (c) 640
  16. 16.Best estimate of 24 × 71? (a) 1400 (b) 140 (c) 14000
  17. 17.Best estimate of 158 + 437? (a) 400 (b) 800 (c) 600
  18. 18.Best estimate of 54 × 17? (a) 10000 (b) 100 (c) 1000
  19. 19.Best estimate of 68 × 72? (a) 49000 (b) 4900 (c) 490
  20. 20.Best estimate of 18 × 39? (a) 800 (b) 8000 (c) 80
  21. 21.Best estimate of 22 × 86? (a) 1800 (b) 180 (c) 18000
  22. 22.Best estimate of 790 + 737? (a) 1300 (b) 1700 (c) 1500
  23. 23.Best estimate of 88 × 26? (a) 27000 (b) 270 (c) 2700
  24. 24.Best estimate of 429 + 762? (a) 1200 (b) 1000 (c) 1400
  25. 25.Best estimate of 69 × 26? (a) 210 (b) 21000 (c) 2100
  26. 26.Best estimate of 289 + 725? (a) 800 (b) 1000 (c) 1200
  27. 27.Best estimate of 49 × 39? (a) 2000 (b) 200 (c) 20000
  28. 28.Best estimate of 652 + 664? (a) 1600 (b) 1400 (c) 1200
  29. 29.Best estimate of 56 × 66? (a) 4200 (b) 420 (c) 42000
  30. 30.Best estimate of 294 + 148? (a) 400 (b) 200 (c) 600
  31. 31.Best estimate of 46 × 87? (a) 4500 (b) 450 (c) 45000
  32. 32.Best estimate of 763 + 723? (a) 1300 (b) 1500 (c) 1700
  33. 33.Best estimate of 578 + 705? (a) 1300 (b) 1500 (c) 1100
  34. 34.Best estimate of 851 + 851? (a) 2000 (b) 1600 (c) 1800
  35. 35.Best estimate of 24 × 12? (a) 2000 (b) 200 (c) 20
  36. 36.Best estimate of 60 × 23? (a) 12000 (b) 120 (c) 1200
  37. 37.Best estimate of 71 × 54? (a) 35000 (b) 350 (c) 3500
  38. 38.Best estimate of 128 + 761? (a) 700 (b) 900 (c) 1100
  39. 39.Best estimate of 868 + 249? (a) 1300 (b) 1100 (c) 900
  40. 40.Best estimate of 17 × 98? (a) 200 (b) 20000 (c) 2000

Answer key

  1. 5400
  2. 1100
  3. 1100
  4. 600
  5. 2500
  6. 900
  7. 700
  8. 1000
  9. 1800
  10. 1600
  11. 1300
  12. 2500
  13. 2000
  14. 3000
  15. 6400
  16. 1400
  17. 600
  18. 1000
  19. 4900
  20. 800
  21. 1800
  22. 1500
  23. 2700
  24. 1200
  25. 2100
  26. 1000
  27. 2000
  28. 1400
  29. 4200
  30. 400
  31. 4500
  32. 1500
  33. 1300
  34. 1800
  35. 200
  36. 1200
  37. 3500
  38. 900
  39. 1100
  40. 2000

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