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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 808 · 40 questions
TalentJR

How to do it in your head (Guess, divide, average): Division: round the divisor to the nearest ten and find the closest multiple of it. Square root: guess the nearest whole root, then divide the number by your guess. Average the guess and the answer of the division, and round to 1 decimal place.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 2934 ÷ 76? (a) 3700 (b) 37 (c) 370
  2. 2.√86 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.0 (d) 9.3
  3. 3.√31 to 1 decimal place? (a) 5.7 (b) 5.4 (c) 5.5 (d) 5.6
  4. 4.Best estimate of 1522 ÷ 44? (a) 380 (b) 3800 (c) 38
  5. 5.Best estimate of 3367 ÷ 44? (a) 840 (b) 84 (c) 8400
  6. 6.√42 to 1 decimal place? (a) 6.5 (b) 6.7 (c) 6.8 (d) 6.6
  7. 7.√43 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.5 (d) 6.3
  8. 8.√23 to 1 decimal place? (a) 5.0 (b) 4.8 (c) 5.1 (d) 4.9
  9. 9.√82 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 9.2
  10. 10.Best estimate of 2013 ÷ 34? (a) 67 (b) 670 (c) 6700
  11. 11.Best estimate of 4087 ÷ 66? (a) 580 (b) 5800 (c) 58
  12. 12.√87 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.3 (d) 9.5
  13. 13.Best estimate of 910 ÷ 61? (a) 15 (b) 150 (c) 1500
  14. 14.Best estimate of 5348 ÷ 56? (a) 890 (b) 8900 (c) 89
  15. 15.√30 to 1 decimal place? (a) 5.4 (b) 5.6 (c) 5.3 (d) 5.5
  16. 16.√38 to 1 decimal place? (a) 6.5 (b) 6.3 (c) 6.4 (d) 6.2
  17. 17.Best estimate of 2196 ÷ 82? (a) 27 (b) 270 (c) 2700
  18. 18.Best estimate of 1096 ÷ 76? (a) 140 (b) 1400 (c) 14
  19. 19.Best estimate of 3466 ÷ 44? (a) 8700 (b) 870 (c) 87
  20. 20.Best estimate of 5351 ÷ 72? (a) 76 (b) 7600 (c) 760
  21. 21.Best estimate of 2311 ÷ 33? (a) 7700 (b) 770 (c) 77
  22. 22.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 9.0
  23. 23.Best estimate of 935 ÷ 52? (a) 190 (b) 1900 (c) 19
  24. 24.Best estimate of 1594 ÷ 32? (a) 53 (b) 5300 (c) 530
  25. 25.√80 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 9.0 (d) 9.2
  26. 26.√34 to 1 decimal place? (a) 5.9 (b) 6.1 (c) 6.0 (d) 5.8
  27. 27.√28 to 1 decimal place? (a) 5.4 (b) 5.6 (c) 5.3 (d) 5.5
  28. 28.Best estimate of 4744 ÷ 77? (a) 5900 (b) 590 (c) 59
  29. 29.√45 to 1 decimal place? (a) 6.9 (b) 6.7 (c) 6.6 (d) 6.8
  30. 30.√85 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.1 (d) 9.4
  31. 31.√55 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.4 (d) 7.7
  32. 32.Best estimate of 2694 ÷ 54? (a) 5400 (b) 54 (c) 540
  33. 33.Best estimate of 1295 ÷ 29? (a) 430 (b) 4300 (c) 43
  34. 34.Best estimate of 2008 ÷ 33? (a) 670 (b) 6700 (c) 67
  35. 35.Best estimate of 1087 ÷ 31? (a) 36 (b) 360 (c) 3600
  36. 36.Best estimate of 3261 ÷ 54? (a) 650 (b) 6500 (c) 65
  37. 37.Best estimate of 1929 ÷ 72? (a) 280 (b) 28 (c) 2800
  38. 38.√24 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 4.6 (d) 4.7
  39. 39.Best estimate of 741 ÷ 22? (a) 3700 (b) 37 (c) 370
  40. 40.√94 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.6 (d) 9.8

Answer key

  1. 37
  2. 9.3
  3. 5.6
  4. 38
  5. 84
  6. 6.5
  7. 6.6
  8. 4.8
  9. 9.1
  10. 67
  11. 58
  12. 9.3
  13. 15
  14. 89
  15. 5.5
  16. 6.2
  17. 27
  18. 14
  19. 87
  20. 76
  21. 77
  22. 8.7
  23. 19
  24. 53
  25. 8.9
  26. 5.8
  27. 5.3
  28. 59
  29. 6.7
  30. 9.2
  31. 7.4
  32. 54
  33. 43
  34. 67
  35. 36
  36. 65
  37. 28
  38. 4.9
  39. 37
  40. 9.7

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