← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 835 · 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.√40 to 1 decimal place? (a) 6.2 (b) 6.5 (c) 6.4 (d) 6.3
  2. 2.Best estimate of 2077 ÷ 46? (a) 4200 (b) 42 (c) 420
  3. 3.√52 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.0 (d) 6.9
  4. 4.Best estimate of 1777 ÷ 33? (a) 5900 (b) 590 (c) 59
  5. 5.√63 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 8.0
  6. 6.√23 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 5.1
  7. 7.√72 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.8
  8. 8.Best estimate of 858 ÷ 32? (a) 29 (b) 290 (c) 2900
  9. 9.√89 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.5 (d) 9.6
  10. 10.√88 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.5 (d) 9.2
  11. 11.Best estimate of 4542 ÷ 56? (a) 760 (b) 7600 (c) 76
  12. 12.Best estimate of 2369 ÷ 43? (a) 5900 (b) 590 (c) 59
  13. 13.Best estimate of 1766 ÷ 21? (a) 8800 (b) 880 (c) 88
  14. 14.√98 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.6 (d) 9.8
  15. 15.Best estimate of 1366 ÷ 46? (a) 270 (b) 27 (c) 2700
  16. 16.Best estimate of 2037 ÷ 72? (a) 29 (b) 2900 (c) 290
  17. 17.Best estimate of 2292 ÷ 38? (a) 5700 (b) 57 (c) 570
  18. 18.Best estimate of 3024 ÷ 42? (a) 76 (b) 760 (c) 7600
  19. 19.√42 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  20. 20.√62 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.8 (d) 7.7
  21. 21.Best estimate of 4505 ÷ 53? (a) 90 (b) 9000 (c) 900
  22. 22.Best estimate of 1766 ÷ 26? (a) 5900 (b) 59 (c) 590
  23. 23.Best estimate of 1470 ÷ 23? (a) 74 (b) 7400 (c) 740
  24. 24.√94 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 9.6
  25. 25.Best estimate of 918 ÷ 39? (a) 2300 (b) 23 (c) 230
  26. 26.Best estimate of 756 ÷ 28? (a) 2500 (b) 25 (c) 250
  27. 27.√78 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 8.9 (d) 8.7
  28. 28.Best estimate of 5879 ÷ 82? (a) 7300 (b) 73 (c) 730
  29. 29.Best estimate of 5667 ÷ 76? (a) 7100 (b) 71 (c) 710
  30. 30.Best estimate of 908 ÷ 27? (a) 300 (b) 3000 (c) 30
  31. 31.Best estimate of 7083 ÷ 77? (a) 890 (b) 89 (c) 8900
  32. 32.√51 to 1 decimal place? (a) 7.1 (b) 6.9 (c) 7.0 (d) 7.2
  33. 33.√30 to 1 decimal place? (a) 5.6 (b) 5.8 (c) 5.7 (d) 5.5
  34. 34.Best estimate of 2993 ÷ 74? (a) 4300 (b) 43 (c) 430
  35. 35.√70 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.4 (d) 8.7
  36. 36.Best estimate of 4448 ÷ 86? (a) 490 (b) 49 (c) 4900
  37. 37.√61 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 8.0 (d) 7.9
  38. 38.√66 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.4 (d) 8.3
  39. 39.√65 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.0 (d) 8.2
  40. 40.Best estimate of 2760 ÷ 67? (a) 39 (b) 390 (c) 3900

Answer key

  1. 6.3
  2. 42
  3. 7.2
  4. 59
  5. 7.9
  6. 4.8
  7. 8.5
  8. 29
  9. 9.4
  10. 9.4
  11. 76
  12. 59
  13. 88
  14. 9.9
  15. 27
  16. 29
  17. 57
  18. 76
  19. 6.5
  20. 7.9
  21. 90
  22. 59
  23. 74
  24. 9.7
  25. 23
  26. 25
  27. 8.8
  28. 73
  29. 71
  30. 30
  31. 89
  32. 7.1
  33. 5.5
  34. 43
  35. 8.4
  36. 49
  37. 7.8
  38. 8.1
  39. 8.1
  40. 39

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