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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 929 · 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 675 + 616? (a) 1500 (b) 1100 (c) 1300
  2. 2.Best estimate of 76 × 52? (a) 40000 (b) 400 (c) 4000
  3. 3.Best estimate of 433 + 615? (a) 1200 (b) 1000 (c) 800
  4. 4.Best estimate of 26 × 50? (a) 1500 (b) 15000 (c) 150
  5. 5.Best estimate of 344 + 432? (a) 500 (b) 700 (c) 900
  6. 6.Best estimate of 132 + 762? (a) 1100 (b) 900 (c) 700
  7. 7.Best estimate of 84 × 79? (a) 64000 (b) 640 (c) 6400
  8. 8.Best estimate of 349 + 461? (a) 600 (b) 800 (c) 1000
  9. 9.Best estimate of 66 × 46? (a) 35000 (b) 3500 (c) 350
  10. 10.Best estimate of 56 × 66? (a) 42000 (b) 4200 (c) 420
  11. 11.Best estimate of 528 + 416? (a) 700 (b) 1100 (c) 900
  12. 12.Best estimate of 632 + 573? (a) 1200 (b) 1000 (c) 1400
  13. 13.Best estimate of 558 + 284? (a) 900 (b) 1100 (c) 700
  14. 14.Best estimate of 78 × 30? (a) 2400 (b) 240 (c) 24000
  15. 15.Best estimate of 91 × 53? (a) 45000 (b) 450 (c) 4500
  16. 16.Best estimate of 707 + 630? (a) 1100 (b) 1500 (c) 1300
  17. 17.Best estimate of 22 × 26? (a) 600 (b) 60 (c) 6000
  18. 18.Best estimate of 371 + 521? (a) 900 (b) 700 (c) 1100
  19. 19.Best estimate of 79 × 38? (a) 320 (b) 3200 (c) 32000
  20. 20.Best estimate of 861 + 130? (a) 1000 (b) 1200 (c) 800
  21. 21.Best estimate of 80 × 17? (a) 1600 (b) 160 (c) 16000
  22. 22.Best estimate of 547 + 459? (a) 1200 (b) 800 (c) 1000
  23. 23.Best estimate of 479 + 261? (a) 600 (b) 800 (c) 1000
  24. 24.Best estimate of 779 + 757? (a) 1800 (b) 1400 (c) 1600
  25. 25.Best estimate of 46 × 66? (a) 3500 (b) 35000 (c) 350
  26. 26.Best estimate of 97 × 74? (a) 70000 (b) 7000 (c) 700
  27. 27.Best estimate of 478 + 185? (a) 700 (b) 900 (c) 500
  28. 28.Best estimate of 82 × 46? (a) 40000 (b) 400 (c) 4000
  29. 29.Best estimate of 69 × 96? (a) 700 (b) 7000 (c) 70000
  30. 30.Best estimate of 186 + 669? (a) 900 (b) 700 (c) 1100
  31. 31.Best estimate of 68 × 58? (a) 420 (b) 4200 (c) 42000
  32. 32.Best estimate of 337 + 590? (a) 1100 (b) 900 (c) 700
  33. 33.Best estimate of 94 × 74? (a) 63000 (b) 6300 (c) 630
  34. 34.Best estimate of 177 + 702? (a) 1100 (b) 900 (c) 700
  35. 35.Best estimate of 62 × 94? (a) 5400 (b) 54000 (c) 540
  36. 36.Best estimate of 495 + 232? (a) 700 (b) 500 (c) 900
  37. 37.Best estimate of 451 + 314? (a) 800 (b) 1000 (c) 600
  38. 38.Best estimate of 873 + 776? (a) 1700 (b) 1900 (c) 1500
  39. 39.Best estimate of 673 + 310? (a) 1000 (b) 1200 (c) 800
  40. 40.Best estimate of 46 × 87? (a) 450 (b) 4500 (c) 45000

Answer key

  1. 1300
  2. 4000
  3. 1000
  4. 1500
  5. 700
  6. 900
  7. 6400
  8. 800
  9. 3500
  10. 4200
  11. 900
  12. 1200
  13. 900
  14. 2400
  15. 4500
  16. 1300
  17. 600
  18. 900
  19. 3200
  20. 1000
  21. 1600
  22. 1000
  23. 800
  24. 1600
  25. 3500
  26. 7000
  27. 700
  28. 4000
  29. 7000
  30. 900
  31. 4200
  32. 900
  33. 6300
  34. 900
  35. 5400
  36. 700
  37. 800
  38. 1700
  39. 1000
  40. 4500

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