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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 508 · 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 13 × 68? (a) 700 (b) 7000 (c) 70
  2. 2.Best estimate of 822 + 832? (a) 1400 (b) 1800 (c) 1600
  3. 3.Best estimate of 52 × 32? (a) 15000 (b) 150 (c) 1500
  4. 4.Best estimate of 702 + 871? (a) 1600 (b) 1400 (c) 1800
  5. 5.Best estimate of 28 × 26? (a) 90 (b) 900 (c) 9000
  6. 6.Best estimate of 582 + 419? (a) 1000 (b) 800 (c) 1200
  7. 7.Best estimate of 710 + 295? (a) 800 (b) 1200 (c) 1000
  8. 8.Best estimate of 282 + 430? (a) 900 (b) 700 (c) 500
  9. 9.Best estimate of 14 × 98? (a) 1000 (b) 10000 (c) 100
  10. 10.Best estimate of 393 + 681? (a) 1300 (b) 1100 (c) 900
  11. 11.Best estimate of 429 + 243? (a) 600 (b) 800 (c) 400
  12. 12.Best estimate of 97 × 93? (a) 9000 (b) 90000 (c) 900
  13. 13.Best estimate of 697 + 125? (a) 800 (b) 600 (c) 1000
  14. 14.Best estimate of 593 + 743? (a) 1500 (b) 1100 (c) 1300
  15. 15.Best estimate of 84 × 77? (a) 64000 (b) 640 (c) 6400
  16. 16.Best estimate of 92 × 81? (a) 720 (b) 72000 (c) 7200
  17. 17.Best estimate of 414 + 736? (a) 900 (b) 1100 (c) 1300
  18. 18.Best estimate of 793 + 693? (a) 1500 (b) 1700 (c) 1300
  19. 19.Best estimate of 88 × 80? (a) 72000 (b) 7200 (c) 720
  20. 20.Best estimate of 841 + 206? (a) 1200 (b) 800 (c) 1000
  21. 21.Best estimate of 44 × 80? (a) 320 (b) 3200 (c) 32000
  22. 22.Best estimate of 22 × 80? (a) 1600 (b) 160 (c) 16000
  23. 23.Best estimate of 677 + 721? (a) 1600 (b) 1400 (c) 1200
  24. 24.Best estimate of 34 × 17? (a) 60 (b) 600 (c) 6000
  25. 25.Best estimate of 60 × 36? (a) 24000 (b) 240 (c) 2400
  26. 26.Best estimate of 32 × 92? (a) 2700 (b) 27000 (c) 270
  27. 27.Best estimate of 34 × 86? (a) 270 (b) 2700 (c) 27000
  28. 28.Best estimate of 56 × 30? (a) 18000 (b) 1800 (c) 180
  29. 29.Best estimate of 32 × 24? (a) 60 (b) 600 (c) 6000
  30. 30.Best estimate of 64 × 58? (a) 3600 (b) 36000 (c) 360
  31. 31.Best estimate of 257 + 534? (a) 800 (b) 1000 (c) 600
  32. 32.Best estimate of 61 × 39? (a) 240 (b) 2400 (c) 24000
  33. 33.Best estimate of 41 × 68? (a) 2800 (b) 28000 (c) 280
  34. 34.Best estimate of 496 + 712? (a) 1000 (b) 1400 (c) 1200
  35. 35.Best estimate of 818 + 308? (a) 1300 (b) 900 (c) 1100
  36. 36.Best estimate of 77 × 13? (a) 80 (b) 8000 (c) 800
  37. 37.Best estimate of 52 × 86? (a) 45000 (b) 4500 (c) 450
  38. 38.Best estimate of 54 × 96? (a) 500 (b) 50000 (c) 5000
  39. 39.Best estimate of 705 + 675? (a) 1400 (b) 1200 (c) 1600
  40. 40.Best estimate of 853 + 141? (a) 800 (b) 1200 (c) 1000

Answer key

  1. 700
  2. 1600
  3. 1500
  4. 1600
  5. 900
  6. 1000
  7. 1000
  8. 700
  9. 1000
  10. 1100
  11. 600
  12. 9000
  13. 800
  14. 1300
  15. 6400
  16. 7200
  17. 1100
  18. 1500
  19. 7200
  20. 1000
  21. 3200
  22. 1600
  23. 1400
  24. 600
  25. 2400
  26. 2700
  27. 2700
  28. 1800
  29. 600
  30. 3600
  31. 800
  32. 2400
  33. 2800
  34. 1200
  35. 1100
  36. 800
  37. 4500
  38. 5000
  39. 1400
  40. 1000

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