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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 122 · 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 718 + 389? (a) 900 (b) 1100 (c) 1300
  2. 2.Best estimate of 26 × 96? (a) 3000 (b) 30000 (c) 300
  3. 3.Best estimate of 542 + 520? (a) 1200 (b) 800 (c) 1000
  4. 4.Best estimate of 83 × 97? (a) 8000 (b) 80000 (c) 800
  5. 5.Best estimate of 148 + 211? (a) 500 (b) 100 (c) 300
  6. 6.Best estimate of 125 + 567? (a) 500 (b) 700 (c) 900
  7. 7.Best estimate of 795 + 763? (a) 1800 (b) 1400 (c) 1600
  8. 8.Best estimate of 210 + 844? (a) 1200 (b) 800 (c) 1000
  9. 9.Best estimate of 94 × 20? (a) 180 (b) 1800 (c) 18000
  10. 10.Best estimate of 805 + 468? (a) 1100 (b) 1300 (c) 1500
  11. 11.Best estimate of 96 × 16? (a) 20000 (b) 2000 (c) 200
  12. 12.Best estimate of 63 × 80? (a) 480 (b) 48000 (c) 4800
  13. 13.Best estimate of 134 + 437? (a) 700 (b) 500 (c) 300
  14. 14.Best estimate of 20 × 73? (a) 140 (b) 14000 (c) 1400
  15. 15.Best estimate of 549 + 867? (a) 1600 (b) 1400 (c) 1200
  16. 16.Best estimate of 304 + 687? (a) 1000 (b) 800 (c) 1200
  17. 17.Best estimate of 59 × 19? (a) 1200 (b) 120 (c) 12000
  18. 18.Best estimate of 329 + 527? (a) 1000 (b) 600 (c) 800
  19. 19.Best estimate of 413 + 619? (a) 1200 (b) 1000 (c) 800
  20. 20.Best estimate of 59 × 21? (a) 12000 (b) 120 (c) 1200
  21. 21.Best estimate of 73 × 16? (a) 1400 (b) 14000 (c) 140
  22. 22.Best estimate of 295 + 727? (a) 1000 (b) 800 (c) 1200
  23. 23.Best estimate of 94 × 64? (a) 540 (b) 5400 (c) 54000
  24. 24.Best estimate of 36 × 41? (a) 16000 (b) 160 (c) 1600
  25. 25.Best estimate of 219 + 216? (a) 400 (b) 200 (c) 600
  26. 26.Best estimate of 14 × 56? (a) 600 (b) 6000 (c) 60
  27. 27.Best estimate of 439 + 633? (a) 1000 (b) 1200 (c) 800
  28. 28.Best estimate of 98 × 47? (a) 5000 (b) 500 (c) 50000
  29. 29.Best estimate of 651 + 306? (a) 1000 (b) 1200 (c) 800
  30. 30.Best estimate of 626 + 224? (a) 800 (b) 1000 (c) 600
  31. 31.Best estimate of 476 + 270? (a) 800 (b) 1000 (c) 600
  32. 32.Best estimate of 701 + 146? (a) 1000 (b) 800 (c) 600
  33. 33.Best estimate of 163 + 712? (a) 1100 (b) 900 (c) 700
  34. 34.Best estimate of 423 + 388? (a) 800 (b) 600 (c) 1000
  35. 35.Best estimate of 46 × 63? (a) 300 (b) 3000 (c) 30000
  36. 36.Best estimate of 14 × 53? (a) 500 (b) 50 (c) 5000
  37. 37.Best estimate of 825 + 282? (a) 1100 (b) 1300 (c) 900
  38. 38.Best estimate of 159 + 574? (a) 600 (b) 1000 (c) 800
  39. 39.Best estimate of 854 + 856? (a) 2000 (b) 1600 (c) 1800
  40. 40.Best estimate of 298 + 293? (a) 800 (b) 400 (c) 600

Answer key

  1. 1100
  2. 3000
  3. 1000
  4. 8000
  5. 300
  6. 700
  7. 1600
  8. 1000
  9. 1800
  10. 1300
  11. 2000
  12. 4800
  13. 500
  14. 1400
  15. 1400
  16. 1000
  17. 1200
  18. 800
  19. 1000
  20. 1200
  21. 1400
  22. 1000
  23. 5400
  24. 1600
  25. 400
  26. 600
  27. 1000
  28. 5000
  29. 1000
  30. 800
  31. 800
  32. 800
  33. 900
  34. 800
  35. 3000
  36. 500
  37. 1100
  38. 800
  39. 1800
  40. 600

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