← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 310 · 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 3800 ÷ 47? (a) 76 (b) 7600 (c) 760
  2. 2.Best estimate of 2149 ÷ 42? (a) 540 (b) 5400 (c) 54
  3. 3.√63 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.8 (d) 8.0
  4. 4.√77 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 8.8 (d) 9.0
  5. 5.√74 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.4 (d) 8.6
  6. 6.√37 to 1 decimal place? (a) 5.8 (b) 6.1 (c) 6.0 (d) 5.9
  7. 7.Best estimate of 4689 ÷ 69? (a) 6700 (b) 67 (c) 670
  8. 8.√23 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 5.0 (d) 4.7
  9. 9.√78 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.7 (d) 8.5
  10. 10.√96 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.7 (d) 9.5
  11. 11.Best estimate of 568 ÷ 36? (a) 140 (b) 1400 (c) 14
  12. 12.Best estimate of 2482 ÷ 54? (a) 500 (b) 5000 (c) 50
  13. 13.Best estimate of 523 ÷ 31? (a) 17 (b) 1700 (c) 170
  14. 14.Best estimate of 1099 ÷ 41? (a) 270 (b) 27 (c) 2700
  15. 15.√92 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.8
  16. 16.Best estimate of 1378 ÷ 84? (a) 170 (b) 1700 (c) 17
  17. 17.Best estimate of 1764 ÷ 31? (a) 590 (b) 59 (c) 5900
  18. 18.√59 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.7 (d) 7.6
  19. 19.√85 to 1 decimal place? (a) 8.9 (b) 9.1 (c) 9.0 (d) 9.2
  20. 20.Best estimate of 3263 ÷ 61? (a) 540 (b) 5400 (c) 54
  21. 21.Best estimate of 2296 ÷ 46? (a) 460 (b) 46 (c) 4600
  22. 22.√29 to 1 decimal place? (a) 5.2 (b) 5.5 (c) 5.4 (d) 5.3
  23. 23.√82 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.1
  24. 24.Best estimate of 3868 ÷ 51? (a) 770 (b) 7700 (c) 77
  25. 25.Best estimate of 1828 ÷ 22? (a) 91 (b) 910 (c) 9100
  26. 26.√53 to 1 decimal place? (a) 7.3 (b) 7.1 (c) 7.2 (d) 7.4
  27. 27.√62 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 8.1 (d) 7.8
  28. 28.Best estimate of 1490 ÷ 52? (a) 30 (b) 300 (c) 3000
  29. 29.√72 to 1 decimal place? (a) 8.3 (b) 8.6 (c) 8.4 (d) 8.5
  30. 30.Best estimate of 6587 ÷ 83? (a) 82 (b) 8200 (c) 820
  31. 31.√26 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.1 (d) 5.0
  32. 32.Best estimate of 812 ÷ 22? (a) 4100 (b) 410 (c) 41
  33. 33.Best estimate of 1296 ÷ 66? (a) 1900 (b) 19 (c) 190
  34. 34.Best estimate of 4933 ÷ 68? (a) 7000 (b) 70 (c) 700
  35. 35.Best estimate of 1558 ÷ 72? (a) 2200 (b) 22 (c) 220
  36. 36.Best estimate of 1332 ÷ 23? (a) 670 (b) 67 (c) 6700
  37. 37.Best estimate of 2416 ÷ 72? (a) 350 (b) 35 (c) 3500
  38. 38.√55 to 1 decimal place? (a) 7.7 (b) 7.5 (c) 7.4 (d) 7.6
  39. 39.√50 to 1 decimal place? (a) 7.3 (b) 7.2 (c) 7.0 (d) 7.1
  40. 40.√84 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.2 (d) 9.3

Answer key

  1. 76
  2. 54
  3. 7.9
  4. 8.8
  5. 8.6
  6. 6.1
  7. 67
  8. 4.8
  9. 8.8
  10. 9.8
  11. 14
  12. 50
  13. 17
  14. 27
  15. 9.6
  16. 17
  17. 59
  18. 7.7
  19. 9.2
  20. 54
  21. 46
  22. 5.4
  23. 9.1
  24. 77
  25. 91
  26. 7.3
  27. 7.9
  28. 30
  29. 8.5
  30. 82
  31. 5.1
  32. 41
  33. 19
  34. 70
  35. 22
  36. 67
  37. 35
  38. 7.4
  39. 7.1
  40. 9.2

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