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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 278 · 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 461 + 704? (a) 1200 (b) 1000 (c) 1400
  2. 2.Best estimate of 42 × 96? (a) 40000 (b) 4000 (c) 400
  3. 3.Best estimate of 344 + 190? (a) 500 (b) 700 (c) 300
  4. 4.Best estimate of 304 + 600? (a) 1100 (b) 900 (c) 700
  5. 5.Best estimate of 872 + 563? (a) 1700 (b) 1500 (c) 1300
  6. 6.Best estimate of 60 × 51? (a) 30000 (b) 3000 (c) 300
  7. 7.Best estimate of 84 × 74? (a) 560 (b) 56000 (c) 5600
  8. 8.Best estimate of 563 + 862? (a) 1300 (b) 1700 (c) 1500
  9. 9.Best estimate of 16 × 42? (a) 8000 (b) 80 (c) 800
  10. 10.Best estimate of 786 + 141? (a) 900 (b) 700 (c) 1100
  11. 11.Best estimate of 615 + 578? (a) 1000 (b) 1400 (c) 1200
  12. 12.Best estimate of 74 × 12? (a) 7000 (b) 700 (c) 70
  13. 13.Best estimate of 330 + 783? (a) 900 (b) 1100 (c) 1300
  14. 14.Best estimate of 30 × 36? (a) 1200 (b) 120 (c) 12000
  15. 15.Best estimate of 711 + 413? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 816 + 832? (a) 1600 (b) 1800 (c) 1400
  17. 17.Best estimate of 521 + 455? (a) 1000 (b) 1200 (c) 800
  18. 18.Best estimate of 14 × 78? (a) 8000 (b) 80 (c) 800
  19. 19.Best estimate of 791 + 541? (a) 1100 (b) 1300 (c) 1500
  20. 20.Best estimate of 42 × 28? (a) 1200 (b) 12000 (c) 120
  21. 21.Best estimate of 397 + 277? (a) 900 (b) 500 (c) 700
  22. 22.Best estimate of 616 + 536? (a) 1300 (b) 1100 (c) 900
  23. 23.Best estimate of 62 × 83? (a) 48000 (b) 4800 (c) 480
  24. 24.Best estimate of 61 × 91? (a) 540 (b) 54000 (c) 5400
  25. 25.Best estimate of 16 × 34? (a) 60 (b) 600 (c) 6000
  26. 26.Best estimate of 755 + 868? (a) 1900 (b) 1500 (c) 1700
  27. 27.Best estimate of 30 × 57? (a) 1800 (b) 18000 (c) 180
  28. 28.Best estimate of 40 × 66? (a) 2800 (b) 280 (c) 28000
  29. 29.Best estimate of 56 × 62? (a) 3600 (b) 36000 (c) 360
  30. 30.Best estimate of 94 × 94? (a) 81000 (b) 8100 (c) 810
  31. 31.Best estimate of 67 × 87? (a) 63000 (b) 6300 (c) 630
  32. 32.Best estimate of 34 × 14? (a) 30 (b) 3000 (c) 300
  33. 33.Best estimate of 96 × 56? (a) 6000 (b) 600 (c) 60000
  34. 34.Best estimate of 27 × 88? (a) 27000 (b) 2700 (c) 270
  35. 35.Best estimate of 844 + 407? (a) 1000 (b) 1400 (c) 1200
  36. 36.Best estimate of 372 + 183? (a) 600 (b) 400 (c) 800
  37. 37.Best estimate of 13 × 68? (a) 7000 (b) 700 (c) 70
  38. 38.Best estimate of 98 × 59? (a) 6000 (b) 60000 (c) 600
  39. 39.Best estimate of 36 × 56? (a) 2400 (b) 240 (c) 24000
  40. 40.Best estimate of 58 × 51? (a) 3000 (b) 30000 (c) 300

Answer key

  1. 1200
  2. 4000
  3. 500
  4. 900
  5. 1500
  6. 3000
  7. 5600
  8. 1500
  9. 800
  10. 900
  11. 1200
  12. 700
  13. 1100
  14. 1200
  15. 1100
  16. 1600
  17. 1000
  18. 800
  19. 1300
  20. 1200
  21. 700
  22. 1100
  23. 4800
  24. 5400
  25. 600
  26. 1700
  27. 1800
  28. 2800
  29. 3600
  30. 8100
  31. 6300
  32. 300
  33. 6000
  34. 2700
  35. 1200
  36. 600
  37. 700
  38. 6000
  39. 2400
  40. 3000

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