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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 317 · 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.√55 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.3 (d) 7.6
  2. 2.√72 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.5 (d) 8.4
  3. 3.Best estimate of 1961 ÷ 64? (a) 330 (b) 33 (c) 3300
  4. 4.Best estimate of 5050 ÷ 62? (a) 8400 (b) 84 (c) 840
  5. 5.√67 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.2 (d) 8.0
  6. 6.√22 to 1 decimal place? (a) 4.8 (b) 4.6 (c) 4.5 (d) 4.7
  7. 7.Best estimate of 483 ÷ 38? (a) 12 (b) 1200 (c) 120
  8. 8.√63 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 8.1 (d) 7.9
  9. 9.Best estimate of 607 ÷ 31? (a) 200 (b) 2000 (c) 20
  10. 10.Best estimate of 2785 ÷ 31? (a) 930 (b) 9300 (c) 93
  11. 11.Best estimate of 6372 ÷ 82? (a) 800 (b) 80 (c) 8000
  12. 12.√61 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 7.8 (d) 8.0
  13. 13.√24 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 4.8 (d) 5.1
  14. 14.Best estimate of 4888 ÷ 83? (a) 61 (b) 6100 (c) 610
  15. 15.√52 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.0 (d) 7.3
  16. 16.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.0
  17. 17.√38 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 5.9 (d) 6.2
  18. 18.√89 to 1 decimal place? (a) 9.2 (b) 9.5 (c) 9.3 (d) 9.4
  19. 19.√40 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.5 (d) 6.3
  20. 20.Best estimate of 804 ÷ 27? (a) 27 (b) 270 (c) 2700
  21. 21.Best estimate of 2996 ÷ 41? (a) 750 (b) 7500 (c) 75
  22. 22.√42 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.5 (d) 6.7
  23. 23.√83 to 1 decimal place? (a) 9.1 (b) 9.4 (c) 9.3 (d) 9.2
  24. 24.Best estimate of 1474 ÷ 48? (a) 2900 (b) 29 (c) 290
  25. 25.√96 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.8 (d) 9.7
  26. 26.Best estimate of 1088 ÷ 29? (a) 3600 (b) 360 (c) 36
  27. 27.Best estimate of 1937 ÷ 21? (a) 970 (b) 9700 (c) 97
  28. 28.Best estimate of 3106 ÷ 57? (a) 5200 (b) 520 (c) 52
  29. 29.Best estimate of 1681 ÷ 56? (a) 280 (b) 28 (c) 2800
  30. 30.√92 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.4
  31. 31.Best estimate of 1196 ÷ 62? (a) 2000 (b) 200 (c) 20
  32. 32.√66 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.2 (d) 8.3
  33. 33.√43 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 6.6
  34. 34.Best estimate of 2398 ÷ 84? (a) 3000 (b) 30 (c) 300
  35. 35.√88 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.3 (d) 9.5
  36. 36.Best estimate of 2324 ÷ 31? (a) 7700 (b) 770 (c) 77
  37. 37.Best estimate of 1556 ÷ 53? (a) 31 (b) 310 (c) 3100
  38. 38.Best estimate of 2857 ÷ 42? (a) 7100 (b) 71 (c) 710
  39. 39.Best estimate of 2351 ÷ 61? (a) 3900 (b) 39 (c) 390
  40. 40.Best estimate of 3194 ÷ 42? (a) 80 (b) 8000 (c) 800

Answer key

  1. 7.4
  2. 8.5
  3. 33
  4. 84
  5. 8.2
  6. 4.7
  7. 12
  8. 7.9
  9. 20
  10. 93
  11. 80
  12. 7.8
  13. 4.9
  14. 61
  15. 7.2
  16. 6.1
  17. 6.2
  18. 9.4
  19. 6.3
  20. 27
  21. 75
  22. 6.5
  23. 9.1
  24. 29
  25. 9.8
  26. 36
  27. 97
  28. 52
  29. 28
  30. 9.6
  31. 20
  32. 8.1
  33. 6.6
  34. 30
  35. 9.4
  36. 77
  37. 31
  38. 71
  39. 39
  40. 80

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