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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 680 · 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 730 + 289? (a) 800 (b) 1200 (c) 1000
  2. 2.Best estimate of 133 + 637? (a) 500 (b) 900 (c) 700
  3. 3.Best estimate of 57 × 96? (a) 60000 (b) 600 (c) 6000
  4. 4.Best estimate of 342 + 228? (a) 500 (b) 700 (c) 300
  5. 5.Best estimate of 47 × 51? (a) 2500 (b) 250 (c) 25000
  6. 6.Best estimate of 18 × 37? (a) 800 (b) 80 (c) 8000
  7. 7.Best estimate of 743 + 370? (a) 1300 (b) 900 (c) 1100
  8. 8.Best estimate of 689 + 659? (a) 1600 (b) 1200 (c) 1400
  9. 9.Best estimate of 620 + 427? (a) 1000 (b) 1200 (c) 800
  10. 10.Best estimate of 164 + 182? (a) 600 (b) 200 (c) 400
  11. 11.Best estimate of 36 × 17? (a) 8000 (b) 80 (c) 800
  12. 12.Best estimate of 659 + 861? (a) 1600 (b) 1800 (c) 1400
  13. 13.Best estimate of 837 + 311? (a) 1100 (b) 900 (c) 1300
  14. 14.Best estimate of 299 + 694? (a) 1000 (b) 800 (c) 1200
  15. 15.Best estimate of 57 × 56? (a) 36000 (b) 3600 (c) 360
  16. 16.Best estimate of 265 + 536? (a) 800 (b) 600 (c) 1000
  17. 17.Best estimate of 77 × 16? (a) 16000 (b) 1600 (c) 160
  18. 18.Best estimate of 304 + 258? (a) 800 (b) 400 (c) 600
  19. 19.Best estimate of 40 × 29? (a) 120 (b) 1200 (c) 12000
  20. 20.Best estimate of 727 + 701? (a) 1400 (b) 1600 (c) 1200
  21. 21.Best estimate of 38 × 14? (a) 4000 (b) 40 (c) 400
  22. 22.Best estimate of 24 × 26? (a) 6000 (b) 600 (c) 60
  23. 23.Best estimate of 414 + 290? (a) 900 (b) 700 (c) 500
  24. 24.Best estimate of 780 + 159? (a) 1200 (b) 800 (c) 1000
  25. 25.Best estimate of 371 + 772? (a) 1400 (b) 1200 (c) 1000
  26. 26.Best estimate of 44 × 53? (a) 2000 (b) 200 (c) 20000
  27. 27.Best estimate of 51 × 41? (a) 200 (b) 20000 (c) 2000
  28. 28.Best estimate of 788 + 489? (a) 1500 (b) 1100 (c) 1300
  29. 29.Best estimate of 38 × 37? (a) 160 (b) 1600 (c) 16000
  30. 30.Best estimate of 69 × 29? (a) 2100 (b) 210 (c) 21000
  31. 31.Best estimate of 357 + 653? (a) 1100 (b) 1300 (c) 900
  32. 32.Best estimate of 268 + 576? (a) 900 (b) 1100 (c) 700
  33. 33.Best estimate of 93 × 93? (a) 8100 (b) 810 (c) 81000
  34. 34.Best estimate of 81 × 66? (a) 5600 (b) 560 (c) 56000
  35. 35.Best estimate of 519 + 506? (a) 1000 (b) 1200 (c) 800
  36. 36.Best estimate of 42 × 49? (a) 2000 (b) 200 (c) 20000
  37. 37.Best estimate of 81 × 26? (a) 24000 (b) 2400 (c) 240
  38. 38.Best estimate of 44 × 82? (a) 320 (b) 3200 (c) 32000
  39. 39.Best estimate of 71 × 27? (a) 2100 (b) 21000 (c) 210
  40. 40.Best estimate of 77 × 56? (a) 48000 (b) 480 (c) 4800

Answer key

  1. 1000
  2. 700
  3. 6000
  4. 500
  5. 2500
  6. 800
  7. 1100
  8. 1400
  9. 1000
  10. 400
  11. 800
  12. 1600
  13. 1100
  14. 1000
  15. 3600
  16. 800
  17. 1600
  18. 600
  19. 1200
  20. 1400
  21. 400
  22. 600
  23. 700
  24. 1000
  25. 1200
  26. 2000
  27. 2000
  28. 1300
  29. 1600
  30. 2100
  31. 1100
  32. 900
  33. 8100
  34. 5600
  35. 1000
  36. 2000
  37. 2400
  38. 3200
  39. 2100
  40. 4800

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