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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 284 · 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 568 + 148? (a) 500 (b) 900 (c) 700
  2. 2.Best estimate of 624 + 132? (a) 900 (b) 700 (c) 500
  3. 3.Best estimate of 571 + 133? (a) 900 (b) 700 (c) 500
  4. 4.Best estimate of 138 + 676? (a) 600 (b) 800 (c) 1000
  5. 5.Best estimate of 261 + 211? (a) 700 (b) 500 (c) 300
  6. 6.Best estimate of 540 + 798? (a) 1300 (b) 1500 (c) 1100
  7. 7.Best estimate of 31 × 41? (a) 12000 (b) 120 (c) 1200
  8. 8.Best estimate of 23 × 58? (a) 120 (b) 1200 (c) 12000
  9. 9.Best estimate of 333 + 865? (a) 1200 (b) 1000 (c) 1400
  10. 10.Best estimate of 19 × 27? (a) 600 (b) 6000 (c) 60
  11. 11.Best estimate of 260 + 415? (a) 900 (b) 700 (c) 500
  12. 12.Best estimate of 96 × 18? (a) 200 (b) 2000 (c) 20000
  13. 13.Best estimate of 20 × 66? (a) 14000 (b) 140 (c) 1400
  14. 14.Best estimate of 77 × 92? (a) 7200 (b) 720 (c) 72000
  15. 15.Best estimate of 502 + 695? (a) 1000 (b) 1400 (c) 1200
  16. 16.Best estimate of 29 × 14? (a) 30 (b) 3000 (c) 300
  17. 17.Best estimate of 430 + 656? (a) 1300 (b) 900 (c) 1100
  18. 18.Best estimate of 46 × 36? (a) 20000 (b) 2000 (c) 200
  19. 19.Best estimate of 80 × 33? (a) 24000 (b) 2400 (c) 240
  20. 20.Best estimate of 76 × 52? (a) 400 (b) 4000 (c) 40000
  21. 21.Best estimate of 736 + 779? (a) 1500 (b) 1300 (c) 1700
  22. 22.Best estimate of 79 × 93? (a) 720 (b) 72000 (c) 7200
  23. 23.Best estimate of 92 × 31? (a) 270 (b) 27000 (c) 2700
  24. 24.Best estimate of 300 + 692? (a) 800 (b) 1200 (c) 1000
  25. 25.Best estimate of 264 + 287? (a) 600 (b) 400 (c) 800
  26. 26.Best estimate of 362 + 579? (a) 800 (b) 1200 (c) 1000
  27. 27.Best estimate of 673 + 460? (a) 1000 (b) 1200 (c) 1400
  28. 28.Best estimate of 77 × 23? (a) 1600 (b) 160 (c) 16000
  29. 29.Best estimate of 51 × 24? (a) 100 (b) 1000 (c) 10000
  30. 30.Best estimate of 362 + 439? (a) 800 (b) 1000 (c) 600
  31. 31.Best estimate of 58 × 24? (a) 1200 (b) 120 (c) 12000
  32. 32.Best estimate of 17 × 60? (a) 1200 (b) 12000 (c) 120
  33. 33.Best estimate of 64 × 51? (a) 300 (b) 3000 (c) 30000
  34. 34.Best estimate of 196 + 477? (a) 500 (b) 700 (c) 900
  35. 35.Best estimate of 39 × 94? (a) 3600 (b) 360 (c) 36000
  36. 36.Best estimate of 706 + 252? (a) 800 (b) 1000 (c) 1200
  37. 37.Best estimate of 26 × 76? (a) 24000 (b) 240 (c) 2400
  38. 38.Best estimate of 146 + 260? (a) 200 (b) 400 (c) 600
  39. 39.Best estimate of 664 + 372? (a) 900 (b) 1100 (c) 1300
  40. 40.Best estimate of 568 + 821? (a) 1600 (b) 1200 (c) 1400

Answer key

  1. 700
  2. 700
  3. 700
  4. 800
  5. 500
  6. 1300
  7. 1200
  8. 1200
  9. 1200
  10. 600
  11. 700
  12. 2000
  13. 1400
  14. 7200
  15. 1200
  16. 300
  17. 1100
  18. 2000
  19. 2400
  20. 4000
  21. 1500
  22. 7200
  23. 2700
  24. 1000
  25. 600
  26. 1000
  27. 1200
  28. 1600
  29. 1000
  30. 800
  31. 1200
  32. 1200
  33. 3000
  34. 700
  35. 3600
  36. 1000
  37. 2400
  38. 400
  39. 1100
  40. 1400

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