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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 48 · 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 125 + 604? (a) 700 (b) 900 (c) 500
  2. 2.Best estimate of 82 × 44? (a) 32000 (b) 3200 (c) 320
  3. 3.Best estimate of 822 + 188? (a) 1200 (b) 1000 (c) 800
  4. 4.Best estimate of 46 × 48? (a) 2500 (b) 25000 (c) 250
  5. 5.Best estimate of 414 + 319? (a) 500 (b) 700 (c) 900
  6. 6.Best estimate of 54 × 39? (a) 200 (b) 2000 (c) 20000
  7. 7.Best estimate of 434 + 464? (a) 900 (b) 700 (c) 1100
  8. 8.Best estimate of 61 × 96? (a) 60000 (b) 6000 (c) 600
  9. 9.Best estimate of 73 × 71? (a) 4900 (b) 49000 (c) 490
  10. 10.Best estimate of 685 + 639? (a) 1300 (b) 1500 (c) 1100
  11. 11.Best estimate of 30 × 16? (a) 6000 (b) 600 (c) 60
  12. 12.Best estimate of 48 × 26? (a) 15000 (b) 1500 (c) 150
  13. 13.Best estimate of 695 + 473? (a) 1400 (b) 1200 (c) 1000
  14. 14.Best estimate of 36 × 77? (a) 32000 (b) 320 (c) 3200
  15. 15.Best estimate of 68 × 88? (a) 6300 (b) 63000 (c) 630
  16. 16.Best estimate of 384 + 544? (a) 900 (b) 700 (c) 1100
  17. 17.Best estimate of 131 + 712? (a) 1000 (b) 800 (c) 600
  18. 18.Best estimate of 239 + 189? (a) 400 (b) 600 (c) 200
  19. 19.Best estimate of 89 × 14? (a) 90 (b) 9000 (c) 900
  20. 20.Best estimate of 299 + 258? (a) 400 (b) 800 (c) 600
  21. 21.Best estimate of 745 + 288? (a) 1200 (b) 1000 (c) 800
  22. 22.Best estimate of 77 × 27? (a) 24000 (b) 2400 (c) 240
  23. 23.Best estimate of 840 + 628? (a) 1600 (b) 1200 (c) 1400
  24. 24.Best estimate of 28 × 53? (a) 15000 (b) 150 (c) 1500
  25. 25.Best estimate of 136 + 656? (a) 800 (b) 600 (c) 1000
  26. 26.Best estimate of 29 × 52? (a) 1500 (b) 15000 (c) 150
  27. 27.Best estimate of 694 + 410? (a) 900 (b) 1100 (c) 1300
  28. 28.Best estimate of 36 × 14? (a) 4000 (b) 400 (c) 40
  29. 29.Best estimate of 66 × 48? (a) 350 (b) 3500 (c) 35000
  30. 30.Best estimate of 47 × 46? (a) 2500 (b) 250 (c) 25000
  31. 31.Best estimate of 76 × 73? (a) 56000 (b) 5600 (c) 560
  32. 32.Best estimate of 82 × 54? (a) 4000 (b) 40000 (c) 400
  33. 33.Best estimate of 24 × 14? (a) 20 (b) 200 (c) 2000
  34. 34.Best estimate of 249 + 649? (a) 1000 (b) 800 (c) 600
  35. 35.Best estimate of 78 × 59? (a) 480 (b) 4800 (c) 48000
  36. 36.Best estimate of 512 + 844? (a) 1300 (b) 1500 (c) 1100
  37. 37.Best estimate of 849 + 636? (a) 1200 (b) 1400 (c) 1600
  38. 38.Best estimate of 92 × 80? (a) 72000 (b) 7200 (c) 720
  39. 39.Best estimate of 835 + 134? (a) 1100 (b) 700 (c) 900
  40. 40.Best estimate of 192 + 274? (a) 300 (b) 500 (c) 700

Answer key

  1. 700
  2. 3200
  3. 1000
  4. 2500
  5. 700
  6. 2000
  7. 900
  8. 6000
  9. 4900
  10. 1300
  11. 600
  12. 1500
  13. 1200
  14. 3200
  15. 6300
  16. 900
  17. 800
  18. 400
  19. 900
  20. 600
  21. 1000
  22. 2400
  23. 1400
  24. 1500
  25. 800
  26. 1500
  27. 1100
  28. 400
  29. 3500
  30. 2500
  31. 5600
  32. 4000
  33. 200
  34. 800
  35. 4800
  36. 1300
  37. 1400
  38. 7200
  39. 900
  40. 500

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