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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 792 · 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 775 + 157? (a) 800 (b) 1000 (c) 1200
  2. 2.Best estimate of 589 + 635? (a) 1000 (b) 1200 (c) 1400
  3. 3.Best estimate of 24 × 68? (a) 140 (b) 14000 (c) 1400
  4. 4.Best estimate of 787 + 712? (a) 1300 (b) 1700 (c) 1500
  5. 5.Best estimate of 816 + 327? (a) 1100 (b) 1300 (c) 900
  6. 6.Best estimate of 626 + 846? (a) 1400 (b) 1200 (c) 1600
  7. 7.Best estimate of 481 + 405? (a) 700 (b) 900 (c) 1100
  8. 8.Best estimate of 33 × 18? (a) 60 (b) 6000 (c) 600
  9. 9.Best estimate of 626 + 173? (a) 600 (b) 800 (c) 1000
  10. 10.Best estimate of 191 + 156? (a) 600 (b) 200 (c) 400
  11. 11.Best estimate of 98 × 90? (a) 90000 (b) 900 (c) 9000
  12. 12.Best estimate of 39 × 38? (a) 160 (b) 16000 (c) 1600
  13. 13.Best estimate of 21 × 63? (a) 1200 (b) 120 (c) 12000
  14. 14.Best estimate of 70 × 37? (a) 28000 (b) 2800 (c) 280
  15. 15.Best estimate of 36 × 39? (a) 1600 (b) 160 (c) 16000
  16. 16.Best estimate of 73 × 66? (a) 4900 (b) 49000 (c) 490
  17. 17.Best estimate of 19 × 26? (a) 600 (b) 6000 (c) 60
  18. 18.Best estimate of 27 × 83? (a) 24000 (b) 240 (c) 2400
  19. 19.Best estimate of 212 + 614? (a) 600 (b) 800 (c) 1000
  20. 20.Best estimate of 92 × 81? (a) 72000 (b) 720 (c) 7200
  21. 21.Best estimate of 40 × 54? (a) 20000 (b) 200 (c) 2000
  22. 22.Best estimate of 34 × 91? (a) 27000 (b) 2700 (c) 270
  23. 23.Best estimate of 851 + 258? (a) 1200 (b) 1400 (c) 1000
  24. 24.Best estimate of 471 + 851? (a) 1200 (b) 1400 (c) 1600
  25. 25.Best estimate of 382 + 761? (a) 1400 (b) 1000 (c) 1200
  26. 26.Best estimate of 693 + 214? (a) 1100 (b) 900 (c) 700
  27. 27.Best estimate of 60 × 40? (a) 24000 (b) 240 (c) 2400
  28. 28.Best estimate of 613 + 252? (a) 1100 (b) 700 (c) 900
  29. 29.Best estimate of 359 + 770? (a) 1400 (b) 1200 (c) 1000
  30. 30.Best estimate of 26 × 91? (a) 2700 (b) 270 (c) 27000
  31. 31.Best estimate of 820 + 852? (a) 1900 (b) 1500 (c) 1700
  32. 32.Best estimate of 27 × 62? (a) 18000 (b) 1800 (c) 180
  33. 33.Best estimate of 20 × 96? (a) 200 (b) 20000 (c) 2000
  34. 34.Best estimate of 758 + 322? (a) 1100 (b) 1300 (c) 900
  35. 35.Best estimate of 51 × 28? (a) 15000 (b) 1500 (c) 150
  36. 36.Best estimate of 36 × 84? (a) 32000 (b) 320 (c) 3200
  37. 37.Best estimate of 47 × 74? (a) 35000 (b) 350 (c) 3500
  38. 38.Best estimate of 69 × 70? (a) 490 (b) 49000 (c) 4900
  39. 39.Best estimate of 125 + 246? (a) 500 (b) 100 (c) 300
  40. 40.Best estimate of 59 × 29? (a) 1800 (b) 18000 (c) 180

Answer key

  1. 1000
  2. 1200
  3. 1400
  4. 1500
  5. 1100
  6. 1400
  7. 900
  8. 600
  9. 800
  10. 400
  11. 9000
  12. 1600
  13. 1200
  14. 2800
  15. 1600
  16. 4900
  17. 600
  18. 2400
  19. 800
  20. 7200
  21. 2000
  22. 2700
  23. 1200
  24. 1400
  25. 1200
  26. 900
  27. 2400
  28. 900
  29. 1200
  30. 2700
  31. 1700
  32. 1800
  33. 2000
  34. 1100
  35. 1500
  36. 3200
  37. 3500
  38. 4900
  39. 300
  40. 1800

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