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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 255 · 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 86 × 46? (a) 4500 (b) 450 (c) 45000
  2. 2.Best estimate of 87 × 26? (a) 2700 (b) 270 (c) 27000
  3. 3.Best estimate of 71 × 98? (a) 7000 (b) 70000 (c) 700
  4. 4.Best estimate of 69 × 58? (a) 42000 (b) 4200 (c) 420
  5. 5.Best estimate of 760 + 156? (a) 1200 (b) 800 (c) 1000
  6. 6.Best estimate of 86 × 12? (a) 9000 (b) 900 (c) 90
  7. 7.Best estimate of 86 × 93? (a) 810 (b) 81000 (c) 8100
  8. 8.Best estimate of 604 + 445? (a) 1000 (b) 1200 (c) 800
  9. 9.Best estimate of 710 + 315? (a) 800 (b) 1000 (c) 1200
  10. 10.Best estimate of 67 × 37? (a) 2800 (b) 28000 (c) 280
  11. 11.Best estimate of 48 × 82? (a) 4000 (b) 400 (c) 40000
  12. 12.Best estimate of 20 × 43? (a) 80 (b) 800 (c) 8000
  13. 13.Best estimate of 52 × 86? (a) 45000 (b) 450 (c) 4500
  14. 14.Best estimate of 609 + 234? (a) 1000 (b) 800 (c) 600
  15. 15.Best estimate of 27 × 50? (a) 150 (b) 1500 (c) 15000
  16. 16.Best estimate of 20 × 86? (a) 180 (b) 1800 (c) 18000
  17. 17.Best estimate of 728 + 745? (a) 1200 (b) 1600 (c) 1400
  18. 18.Best estimate of 726 + 251? (a) 1200 (b) 1000 (c) 800
  19. 19.Best estimate of 196 + 455? (a) 900 (b) 500 (c) 700
  20. 20.Best estimate of 14 × 84? (a) 800 (b) 8000 (c) 80
  21. 21.Best estimate of 491 + 296? (a) 600 (b) 800 (c) 1000
  22. 22.Best estimate of 88 × 31? (a) 2700 (b) 27000 (c) 270
  23. 23.Best estimate of 579 + 198? (a) 800 (b) 600 (c) 1000
  24. 24.Best estimate of 17 × 88? (a) 18000 (b) 1800 (c) 180
  25. 25.Best estimate of 608 + 633? (a) 1000 (b) 1200 (c) 1400
  26. 26.Best estimate of 445 + 479? (a) 700 (b) 1100 (c) 900
  27. 27.Best estimate of 299 + 162? (a) 700 (b) 300 (c) 500
  28. 28.Best estimate of 56 × 33? (a) 1800 (b) 180 (c) 18000
  29. 29.Best estimate of 70 × 18? (a) 1400 (b) 140 (c) 14000
  30. 30.Best estimate of 16 × 76? (a) 1600 (b) 16000 (c) 160
  31. 31.Best estimate of 91 × 23? (a) 18000 (b) 1800 (c) 180
  32. 32.Best estimate of 853 + 736? (a) 1800 (b) 1600 (c) 1400
  33. 33.Best estimate of 287 + 243? (a) 500 (b) 300 (c) 700
  34. 34.Best estimate of 740 + 657? (a) 1200 (b) 1600 (c) 1400
  35. 35.Best estimate of 385 + 260? (a) 500 (b) 700 (c) 900
  36. 36.Best estimate of 21 × 47? (a) 100 (b) 1000 (c) 10000
  37. 37.Best estimate of 19 × 32? (a) 6000 (b) 600 (c) 60
  38. 38.Best estimate of 854 + 591? (a) 1700 (b) 1500 (c) 1300
  39. 39.Best estimate of 49 × 97? (a) 5000 (b) 500 (c) 50000
  40. 40.Best estimate of 28 × 97? (a) 300 (b) 30000 (c) 3000

Answer key

  1. 4500
  2. 2700
  3. 7000
  4. 4200
  5. 1000
  6. 900
  7. 8100
  8. 1000
  9. 1000
  10. 2800
  11. 4000
  12. 800
  13. 4500
  14. 800
  15. 1500
  16. 1800
  17. 1400
  18. 1000
  19. 700
  20. 800
  21. 800
  22. 2700
  23. 800
  24. 1800
  25. 1200
  26. 900
  27. 500
  28. 1800
  29. 1400
  30. 1600
  31. 1800
  32. 1600
  33. 500
  34. 1400
  35. 700
  36. 1000
  37. 600
  38. 1500
  39. 5000
  40. 3000

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