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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 756 · 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 162 + 669? (a) 700 (b) 900 (c) 1100
  2. 2.Best estimate of 44 × 61? (a) 240 (b) 24000 (c) 2400
  3. 3.Best estimate of 444 + 259? (a) 500 (b) 900 (c) 700
  4. 4.Best estimate of 767 + 622? (a) 1400 (b) 1200 (c) 1600
  5. 5.Best estimate of 348 + 485? (a) 1000 (b) 600 (c) 800
  6. 6.Best estimate of 59 × 70? (a) 42000 (b) 420 (c) 4200
  7. 7.Best estimate of 175 + 356? (a) 600 (b) 800 (c) 400
  8. 8.Best estimate of 690 + 871? (a) 1400 (b) 1600 (c) 1800
  9. 9.Best estimate of 32 × 34? (a) 9000 (b) 90 (c) 900
  10. 10.Best estimate of 317 + 859? (a) 1200 (b) 1400 (c) 1000
  11. 11.Best estimate of 642 + 489? (a) 1100 (b) 900 (c) 1300
  12. 12.Best estimate of 551 + 324? (a) 1100 (b) 900 (c) 700
  13. 13.Best estimate of 433 + 300? (a) 700 (b) 500 (c) 900
  14. 14.Best estimate of 16 × 26? (a) 60 (b) 6000 (c) 600
  15. 15.Best estimate of 220 + 268? (a) 500 (b) 300 (c) 700
  16. 16.Best estimate of 141 + 338? (a) 400 (b) 200 (c) 600
  17. 17.Best estimate of 541 + 143? (a) 400 (b) 800 (c) 600
  18. 18.Best estimate of 665 + 767? (a) 1700 (b) 1500 (c) 1300
  19. 19.Best estimate of 578 + 222? (a) 600 (b) 1000 (c) 800
  20. 20.Best estimate of 61 × 26? (a) 1800 (b) 18000 (c) 180
  21. 21.Best estimate of 76 × 71? (a) 56000 (b) 560 (c) 5600
  22. 22.Best estimate of 58 × 26? (a) 18000 (b) 1800 (c) 180
  23. 23.Best estimate of 317 + 873? (a) 1400 (b) 1200 (c) 1000
  24. 24.Best estimate of 228 + 132? (a) 500 (b) 100 (c) 300
  25. 25.Best estimate of 27 × 63? (a) 1800 (b) 18000 (c) 180
  26. 26.Best estimate of 720 + 546? (a) 1000 (b) 1400 (c) 1200
  27. 27.Best estimate of 56 × 64? (a) 36000 (b) 360 (c) 3600
  28. 28.Best estimate of 651 + 285? (a) 1200 (b) 1000 (c) 800
  29. 29.Best estimate of 526 + 861? (a) 1400 (b) 1600 (c) 1200
  30. 30.Best estimate of 23 × 77? (a) 1600 (b) 160 (c) 16000
  31. 31.Best estimate of 63 × 36? (a) 24000 (b) 2400 (c) 240
  32. 32.Best estimate of 53 × 92? (a) 45000 (b) 450 (c) 4500
  33. 33.Best estimate of 23 × 16? (a) 400 (b) 40 (c) 4000
  34. 34.Best estimate of 43 × 18? (a) 80 (b) 800 (c) 8000
  35. 35.Best estimate of 32 × 13? (a) 3000 (b) 30 (c) 300
  36. 36.Best estimate of 540 + 361? (a) 900 (b) 700 (c) 1100
  37. 37.Best estimate of 288 + 195? (a) 300 (b) 700 (c) 500
  38. 38.Best estimate of 467 + 447? (a) 900 (b) 700 (c) 1100
  39. 39.Best estimate of 14 × 28? (a) 30 (b) 3000 (c) 300
  40. 40.Best estimate of 758 + 555? (a) 1600 (b) 1400 (c) 1200

Answer key

  1. 900
  2. 2400
  3. 700
  4. 1400
  5. 800
  6. 4200
  7. 600
  8. 1600
  9. 900
  10. 1200
  11. 1100
  12. 900
  13. 700
  14. 600
  15. 500
  16. 400
  17. 600
  18. 1500
  19. 800
  20. 1800
  21. 5600
  22. 1800
  23. 1200
  24. 300
  25. 1800
  26. 1200
  27. 3600
  28. 1000
  29. 1400
  30. 1600
  31. 2400
  32. 4500
  33. 400
  34. 800
  35. 300
  36. 900
  37. 500
  38. 900
  39. 300
  40. 1400

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