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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 28 · 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 578 + 708? (a) 1300 (b) 1100 (c) 1500
  2. 2.Best estimate of 19 × 26? (a) 6000 (b) 600 (c) 60
  3. 3.Best estimate of 696 + 172? (a) 900 (b) 700 (c) 1100
  4. 4.Best estimate of 42 × 71? (a) 280 (b) 2800 (c) 28000
  5. 5.Best estimate of 266 + 708? (a) 1000 (b) 800 (c) 1200
  6. 6.Best estimate of 187 + 298? (a) 700 (b) 300 (c) 500
  7. 7.Best estimate of 19 × 68? (a) 140 (b) 1400 (c) 14000
  8. 8.Best estimate of 658 + 706? (a) 1200 (b) 1400 (c) 1600
  9. 9.Best estimate of 79 × 86? (a) 7200 (b) 72000 (c) 720
  10. 10.Best estimate of 125 + 671? (a) 1000 (b) 600 (c) 800
  11. 11.Best estimate of 67 × 30? (a) 2100 (b) 210 (c) 21000
  12. 12.Best estimate of 663 + 813? (a) 1300 (b) 1500 (c) 1700
  13. 13.Best estimate of 63 × 32? (a) 18000 (b) 1800 (c) 180
  14. 14.Best estimate of 319 + 609? (a) 900 (b) 700 (c) 1100
  15. 15.Best estimate of 872 + 798? (a) 1900 (b) 1500 (c) 1700
  16. 16.Best estimate of 569 + 219? (a) 1000 (b) 800 (c) 600
  17. 17.Best estimate of 93 × 27? (a) 270 (b) 2700 (c) 27000
  18. 18.Best estimate of 429 + 776? (a) 1200 (b) 1400 (c) 1000
  19. 19.Best estimate of 517 + 609? (a) 1100 (b) 900 (c) 1300
  20. 20.Best estimate of 28 × 33? (a) 9000 (b) 90 (c) 900
  21. 21.Best estimate of 97 × 64? (a) 60000 (b) 6000 (c) 600
  22. 22.Best estimate of 454 + 194? (a) 900 (b) 700 (c) 500
  23. 23.Best estimate of 247 + 163? (a) 600 (b) 200 (c) 400
  24. 24.Best estimate of 71 × 96? (a) 7000 (b) 700 (c) 70000
  25. 25.Best estimate of 80 × 23? (a) 1600 (b) 16000 (c) 160
  26. 26.Best estimate of 52 × 26? (a) 1500 (b) 150 (c) 15000
  27. 27.Best estimate of 219 + 784? (a) 800 (b) 1000 (c) 1200
  28. 28.Best estimate of 12 × 94? (a) 9000 (b) 900 (c) 90
  29. 29.Best estimate of 404 + 328? (a) 700 (b) 900 (c) 500
  30. 30.Best estimate of 72 × 54? (a) 35000 (b) 350 (c) 3500
  31. 31.Best estimate of 563 + 199? (a) 600 (b) 1000 (c) 800
  32. 32.Best estimate of 96 × 66? (a) 7000 (b) 700 (c) 70000
  33. 33.Best estimate of 26 × 67? (a) 2100 (b) 210 (c) 21000
  34. 34.Best estimate of 77 × 76? (a) 640 (b) 64000 (c) 6400
  35. 35.Best estimate of 67 × 79? (a) 5600 (b) 56000 (c) 560
  36. 36.Best estimate of 339 + 300? (a) 600 (b) 800 (c) 400
  37. 37.Best estimate of 72 × 44? (a) 2800 (b) 280 (c) 28000
  38. 38.Best estimate of 326 + 590? (a) 700 (b) 900 (c) 1100
  39. 39.Best estimate of 62 × 73? (a) 420 (b) 4200 (c) 42000
  40. 40.Best estimate of 96 × 50? (a) 50000 (b) 5000 (c) 500

Answer key

  1. 1300
  2. 600
  3. 900
  4. 2800
  5. 1000
  6. 500
  7. 1400
  8. 1400
  9. 7200
  10. 800
  11. 2100
  12. 1500
  13. 1800
  14. 900
  15. 1700
  16. 800
  17. 2700
  18. 1200
  19. 1100
  20. 900
  21. 6000
  22. 700
  23. 400
  24. 7000
  25. 1600
  26. 1500
  27. 1000
  28. 900
  29. 700
  30. 3500
  31. 800
  32. 7000
  33. 2100
  34. 6400
  35. 5600
  36. 600
  37. 2800
  38. 900
  39. 4200
  40. 5000

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