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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 704 · 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 36 × 83? (a) 320 (b) 3200 (c) 32000
  2. 2.Best estimate of 758 + 309? (a) 1300 (b) 900 (c) 1100
  3. 3.Best estimate of 69 × 46? (a) 3500 (b) 35000 (c) 350
  4. 4.Best estimate of 76 × 61? (a) 4800 (b) 48000 (c) 480
  5. 5.Best estimate of 649 + 580? (a) 1400 (b) 1200 (c) 1000
  6. 6.Best estimate of 39 × 63? (a) 24000 (b) 2400 (c) 240
  7. 7.Best estimate of 32 × 13? (a) 30 (b) 3000 (c) 300
  8. 8.Best estimate of 82 × 76? (a) 640 (b) 64000 (c) 6400
  9. 9.Best estimate of 301 + 618? (a) 900 (b) 700 (c) 1100
  10. 10.Best estimate of 281 + 334? (a) 800 (b) 400 (c) 600
  11. 11.Best estimate of 466 + 608? (a) 900 (b) 1100 (c) 1300
  12. 12.Best estimate of 68 × 24? (a) 14000 (b) 140 (c) 1400
  13. 13.Best estimate of 77 × 46? (a) 4000 (b) 40000 (c) 400
  14. 14.Best estimate of 70 × 24? (a) 140 (b) 1400 (c) 14000
  15. 15.Best estimate of 16 × 57? (a) 12000 (b) 120 (c) 1200
  16. 16.Best estimate of 473 + 531? (a) 1200 (b) 800 (c) 1000
  17. 17.Best estimate of 46 × 76? (a) 4000 (b) 40000 (c) 400
  18. 18.Best estimate of 93 × 97? (a) 9000 (b) 900 (c) 90000
  19. 19.Best estimate of 59 × 88? (a) 5400 (b) 54000 (c) 540
  20. 20.Best estimate of 60 × 39? (a) 240 (b) 24000 (c) 2400
  21. 21.Best estimate of 89 × 26? (a) 2700 (b) 270 (c) 27000
  22. 22.Best estimate of 80 × 17? (a) 1600 (b) 16000 (c) 160
  23. 23.Best estimate of 72 × 79? (a) 560 (b) 5600 (c) 56000
  24. 24.Best estimate of 46 × 31? (a) 15000 (b) 1500 (c) 150
  25. 25.Best estimate of 43 × 28? (a) 12000 (b) 1200 (c) 120
  26. 26.Best estimate of 64 × 31? (a) 180 (b) 18000 (c) 1800
  27. 27.Best estimate of 17 × 53? (a) 10000 (b) 1000 (c) 100
  28. 28.Best estimate of 301 + 540? (a) 800 (b) 1000 (c) 600
  29. 29.Best estimate of 233 + 335? (a) 500 (b) 700 (c) 300
  30. 30.Best estimate of 542 + 218? (a) 700 (b) 900 (c) 500
  31. 31.Best estimate of 83 × 62? (a) 4800 (b) 480 (c) 48000
  32. 32.Best estimate of 707 + 130? (a) 800 (b) 1000 (c) 600
  33. 33.Best estimate of 30 × 66? (a) 210 (b) 21000 (c) 2100
  34. 34.Best estimate of 32 × 33? (a) 900 (b) 9000 (c) 90
  35. 35.Best estimate of 73 × 84? (a) 56000 (b) 560 (c) 5600
  36. 36.Best estimate of 796 + 523? (a) 1500 (b) 1100 (c) 1300
  37. 37.Best estimate of 458 + 614? (a) 1100 (b) 900 (c) 1300
  38. 38.Best estimate of 612 + 374? (a) 1200 (b) 800 (c) 1000
  39. 39.Best estimate of 69 × 86? (a) 6300 (b) 63000 (c) 630
  40. 40.Best estimate of 44 × 17? (a) 8000 (b) 80 (c) 800

Answer key

  1. 3200
  2. 1100
  3. 3500
  4. 4800
  5. 1200
  6. 2400
  7. 300
  8. 6400
  9. 900
  10. 600
  11. 1100
  12. 1400
  13. 4000
  14. 1400
  15. 1200
  16. 1000
  17. 4000
  18. 9000
  19. 5400
  20. 2400
  21. 2700
  22. 1600
  23. 5600
  24. 1500
  25. 1200
  26. 1800
  27. 1000
  28. 800
  29. 500
  30. 700
  31. 4800
  32. 800
  33. 2100
  34. 900
  35. 5600
  36. 1300
  37. 1100
  38. 1000
  39. 6300
  40. 800

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