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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 872 · 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 1332 ÷ 34? (a) 440 (b) 4400 (c) 44
  2. 2.√29 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.4 (d) 5.5
  3. 3.√74 to 1 decimal place? (a) 8.5 (b) 8.7 (c) 8.6 (d) 8.4
  4. 4.√44 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.7 (d) 6.8
  5. 5.Best estimate of 1549 ÷ 37? (a) 3900 (b) 39 (c) 390
  6. 6.√37 to 1 decimal place? (a) 5.8 (b) 6.1 (c) 5.9 (d) 6.0
  7. 7.√92 to 1 decimal place? (a) 9.5 (b) 9.7 (c) 9.6 (d) 9.4
  8. 8.√28 to 1 decimal place? (a) 5.0 (b) 5.1 (c) 5.3 (d) 5.2
  9. 9.Best estimate of 3700 ÷ 53? (a) 740 (b) 7400 (c) 74
  10. 10.Best estimate of 2517 ÷ 42? (a) 6300 (b) 63 (c) 630
  11. 11.Best estimate of 1565 ÷ 24? (a) 7800 (b) 780 (c) 78
  12. 12.√30 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.7 (d) 5.6
  13. 13.√59 to 1 decimal place? (a) 7.8 (b) 7.5 (c) 7.7 (d) 7.6
  14. 14.Best estimate of 526 ÷ 32? (a) 180 (b) 18 (c) 1800
  15. 15.Best estimate of 5232 ÷ 71? (a) 75 (b) 7500 (c) 750
  16. 16.Best estimate of 2451 ÷ 32? (a) 8200 (b) 820 (c) 82
  17. 17.Best estimate of 3505 ÷ 83? (a) 44 (b) 4400 (c) 440
  18. 18.Best estimate of 1112 ÷ 34? (a) 370 (b) 37 (c) 3700
  19. 19.Best estimate of 6971 ÷ 82? (a) 8700 (b) 87 (c) 870
  20. 20.√80 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 9.2
  21. 21.√90 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.4 (d) 9.3
  22. 22.√67 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.4 (d) 8.2
  23. 23.Best estimate of 763 ÷ 29? (a) 250 (b) 25 (c) 2500
  24. 24.Best estimate of 3914 ÷ 47? (a) 780 (b) 78 (c) 7800
  25. 25.√40 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.4 (d) 6.5
  26. 26.Best estimate of 2078 ÷ 22? (a) 10400 (b) 104 (c) 1040
  27. 27.Best estimate of 586 ÷ 22? (a) 290 (b) 29 (c) 2900
  28. 28.Best estimate of 4380 ÷ 88? (a) 490 (b) 4900 (c) 49
  29. 29.√45 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 6.6 (d) 6.7
  30. 30.Best estimate of 719 ÷ 22? (a) 36 (b) 3600 (c) 360
  31. 31.√76 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 9.0 (d) 8.7
  32. 32.Best estimate of 1109 ÷ 48? (a) 22 (b) 2200 (c) 220
  33. 33.Best estimate of 1685 ÷ 38? (a) 42 (b) 4200 (c) 420
  34. 34.Best estimate of 2683 ÷ 88? (a) 3000 (b) 300 (c) 30
  35. 35.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 10.0 (d) 9.7
  36. 36.√65 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 8.2 (d) 7.9
  37. 37.√56 to 1 decimal place? (a) 7.5 (b) 7.2 (c) 7.3 (d) 7.4
  38. 38.√47 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 7.1 (d) 6.8
  39. 39.Best estimate of 901 ÷ 36? (a) 23 (b) 230 (c) 2300
  40. 40.Best estimate of 1049 ÷ 41? (a) 26 (b) 260 (c) 2600

Answer key

  1. 44
  2. 5.4
  3. 8.6
  4. 6.6
  5. 39
  6. 6.1
  7. 9.6
  8. 5.3
  9. 74
  10. 63
  11. 78
  12. 5.5
  13. 7.7
  14. 18
  15. 75
  16. 82
  17. 44
  18. 37
  19. 87
  20. 8.9
  21. 9.5
  22. 8.2
  23. 25
  24. 78
  25. 6.3
  26. 104
  27. 29
  28. 49
  29. 6.7
  30. 36
  31. 8.7
  32. 22
  33. 42
  34. 30
  35. 9.9
  36. 8.1
  37. 7.5
  38. 6.9
  39. 23
  40. 26

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