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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 273 · 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 752 + 246? (a) 1200 (b) 1000 (c) 800
  2. 2.Best estimate of 734 + 655? (a) 1400 (b) 1600 (c) 1200
  3. 3.Best estimate of 47 × 12? (a) 5000 (b) 50 (c) 500
  4. 4.Best estimate of 16 × 16? (a) 400 (b) 4000 (c) 40
  5. 5.Best estimate of 32 × 13? (a) 30 (b) 300 (c) 3000
  6. 6.Best estimate of 96 × 78? (a) 800 (b) 80000 (c) 8000
  7. 7.Best estimate of 230 + 381? (a) 800 (b) 600 (c) 400
  8. 8.Best estimate of 632 + 626? (a) 1000 (b) 1400 (c) 1200
  9. 9.Best estimate of 30 × 97? (a) 30000 (b) 3000 (c) 300
  10. 10.Best estimate of 863 + 398? (a) 1100 (b) 1500 (c) 1300
  11. 11.Best estimate of 860 + 227? (a) 1100 (b) 1300 (c) 900
  12. 12.Best estimate of 840 + 600? (a) 1200 (b) 1600 (c) 1400
  13. 13.Best estimate of 96 × 49? (a) 500 (b) 5000 (c) 50000
  14. 14.Best estimate of 87 × 61? (a) 54000 (b) 540 (c) 5400
  15. 15.Best estimate of 681 + 201? (a) 900 (b) 1100 (c) 700
  16. 16.Best estimate of 56 × 61? (a) 360 (b) 3600 (c) 36000
  17. 17.Best estimate of 84 × 79? (a) 6400 (b) 640 (c) 64000
  18. 18.Best estimate of 94 × 13? (a) 90 (b) 900 (c) 9000
  19. 19.Best estimate of 23 × 63? (a) 12000 (b) 1200 (c) 120
  20. 20.Best estimate of 74 × 83? (a) 5600 (b) 56000 (c) 560
  21. 21.Best estimate of 123 + 836? (a) 700 (b) 1100 (c) 900
  22. 22.Best estimate of 22 × 21? (a) 400 (b) 40 (c) 4000
  23. 23.Best estimate of 69 × 44? (a) 2800 (b) 280 (c) 28000
  24. 24.Best estimate of 831 + 823? (a) 1600 (b) 1400 (c) 1800
  25. 25.Best estimate of 96 × 82? (a) 8000 (b) 80000 (c) 800
  26. 26.Best estimate of 92 × 90? (a) 81000 (b) 810 (c) 8100
  27. 27.Best estimate of 327 + 418? (a) 500 (b) 900 (c) 700
  28. 28.Best estimate of 413 + 414? (a) 800 (b) 1000 (c) 600
  29. 29.Best estimate of 669 + 305? (a) 800 (b) 1000 (c) 1200
  30. 30.Best estimate of 76 × 14? (a) 8000 (b) 800 (c) 80
  31. 31.Best estimate of 20 × 16? (a) 4000 (b) 400 (c) 40
  32. 32.Best estimate of 204 + 238? (a) 600 (b) 200 (c) 400
  33. 33.Best estimate of 39 × 56? (a) 2400 (b) 24000 (c) 240
  34. 34.Best estimate of 76 × 33? (a) 24000 (b) 2400 (c) 240
  35. 35.Best estimate of 646 + 800? (a) 1200 (b) 1400 (c) 1600
  36. 36.Best estimate of 56 × 59? (a) 3600 (b) 36000 (c) 360
  37. 37.Best estimate of 702 + 169? (a) 1100 (b) 700 (c) 900
  38. 38.Best estimate of 83 × 52? (a) 40000 (b) 4000 (c) 400
  39. 39.Best estimate of 56 × 22? (a) 12000 (b) 120 (c) 1200
  40. 40.Best estimate of 23 × 22? (a) 4000 (b) 40 (c) 400

Answer key

  1. 1000
  2. 1400
  3. 500
  4. 400
  5. 300
  6. 8000
  7. 600
  8. 1200
  9. 3000
  10. 1300
  11. 1100
  12. 1400
  13. 5000
  14. 5400
  15. 900
  16. 3600
  17. 6400
  18. 900
  19. 1200
  20. 5600
  21. 900
  22. 400
  23. 2800
  24. 1600
  25. 8000
  26. 8100
  27. 700
  28. 800
  29. 1000
  30. 800
  31. 400
  32. 400
  33. 2400
  34. 2400
  35. 1400
  36. 3600
  37. 900
  38. 4000
  39. 1200
  40. 400

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