← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 943 · 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 700 ÷ 49? (a) 1400 (b) 14 (c) 140
  2. 2.√98 to 1 decimal place? (a) 10.2 (b) 10.0 (c) 10.1 (d) 9.9
  3. 3.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  4. 4.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.4 (d) 8.3
  5. 5.√37 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.1 (d) 6.2
  6. 6.Best estimate of 2503 ÷ 28? (a) 83 (b) 8300 (c) 830
  7. 7.Best estimate of 2942 ÷ 62? (a) 4900 (b) 49 (c) 490
  8. 8.√41 to 1 decimal place? (a) 6.1 (b) 6.4 (c) 6.3 (d) 6.2
  9. 9.Best estimate of 2191 ÷ 48? (a) 44 (b) 440 (c) 4400
  10. 10.Best estimate of 4924 ÷ 86? (a) 55 (b) 550 (c) 5500
  11. 11.√35 to 1 decimal place? (a) 6.1 (b) 5.9 (c) 6.2 (d) 6.0
  12. 12.√80 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 9.1 (d) 8.9
  13. 13.Best estimate of 6853 ÷ 77? (a) 8600 (b) 860 (c) 86
  14. 14.Best estimate of 1000 ÷ 24? (a) 5000 (b) 50 (c) 500
  15. 15.Best estimate of 583 ÷ 42? (a) 1500 (b) 150 (c) 15
  16. 16.Best estimate of 922 ÷ 62? (a) 150 (b) 15 (c) 1500
  17. 17.Best estimate of 3599 ÷ 46? (a) 72 (b) 720 (c) 7200
  18. 18.√58 to 1 decimal place? (a) 7.8 (b) 7.5 (c) 7.7 (d) 7.6
  19. 19.Best estimate of 5143 ÷ 76? (a) 6400 (b) 64 (c) 640
  20. 20.√59 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.7 (d) 7.5
  21. 21.Best estimate of 5059 ÷ 56? (a) 84 (b) 840 (c) 8400
  22. 22.√31 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.6 (d) 5.3
  23. 23.√29 to 1 decimal place? (a) 5.6 (b) 5.4 (c) 5.5 (d) 5.3
  24. 24.Best estimate of 5042 ÷ 56? (a) 84 (b) 840 (c) 8400
  25. 25.Best estimate of 2477 ÷ 33? (a) 83 (b) 8300 (c) 830
  26. 26.√87 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.4 (d) 9.2
  27. 27.√24 to 1 decimal place? (a) 4.9 (b) 4.8 (c) 4.7 (d) 5.0
  28. 28.√26 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.0 (d) 5.1
  29. 29.√30 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.6 (d) 5.8
  30. 30.Best estimate of 3909 ÷ 42? (a) 980 (b) 9800 (c) 98
  31. 31.Best estimate of 1383 ÷ 43? (a) 3500 (b) 35 (c) 350
  32. 32.√90 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.5 (d) 9.4
  33. 33.√61 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.8
  34. 34.Best estimate of 843 ÷ 29? (a) 280 (b) 2800 (c) 28
  35. 35.Best estimate of 2800 ÷ 49? (a) 56 (b) 560 (c) 5600
  36. 36.Best estimate of 989 ÷ 26? (a) 330 (b) 3300 (c) 33
  37. 37.Best estimate of 2471 ÷ 29? (a) 8200 (b) 82 (c) 820
  38. 38.Best estimate of 4854 ÷ 66? (a) 690 (b) 69 (c) 6900
  39. 39.Best estimate of 3031 ÷ 38? (a) 760 (b) 7600 (c) 76
  40. 40.Best estimate of 2540 ÷ 47? (a) 51 (b) 510 (c) 5100

Answer key

  1. 14
  2. 9.9
  3. 6.3
  4. 8.1
  5. 6.1
  6. 83
  7. 49
  8. 6.4
  9. 44
  10. 55
  11. 5.9
  12. 8.9
  13. 86
  14. 50
  15. 15
  16. 15
  17. 72
  18. 7.6
  19. 64
  20. 7.7
  21. 84
  22. 5.6
  23. 5.4
  24. 84
  25. 83
  26. 9.3
  27. 4.9
  28. 5.1
  29. 5.5
  30. 98
  31. 35
  32. 9.5
  33. 7.8
  34. 28
  35. 56
  36. 33
  37. 82
  38. 69
  39. 76
  40. 51

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths