← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 192 · 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) 7.7 (b) 7.6 (c) 7.4 (d) 7.5
  2. 2.√48 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.0 (d) 6.7
  3. 3.Best estimate of 3120 ÷ 36? (a) 78 (b) 780 (c) 7800
  4. 4.Best estimate of 5347 ÷ 74? (a) 760 (b) 7600 (c) 76
  5. 5.√92 to 1 decimal place? (a) 9.5 (b) 9.8 (c) 9.6 (d) 9.7
  6. 6.√82 to 1 decimal place? (a) 9.1 (b) 8.8 (c) 9.0 (d) 8.9
  7. 7.Best estimate of 1236 ÷ 34? (a) 410 (b) 4100 (c) 41
  8. 8.√50 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 6.9 (d) 7.0
  9. 9.Best estimate of 680 ÷ 27? (a) 23 (b) 2300 (c) 230
  10. 10.√89 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.4 (d) 9.5
  11. 11.Best estimate of 2798 ÷ 34? (a) 9300 (b) 930 (c) 93
  12. 12.√23 to 1 decimal place? (a) 4.6 (b) 4.8 (c) 4.7 (d) 4.5
  13. 13.Best estimate of 907 ÷ 32? (a) 300 (b) 3000 (c) 30
  14. 14.√28 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.4 (d) 5.3
  15. 15.Best estimate of 1648 ÷ 62? (a) 270 (b) 27 (c) 2700
  16. 16.Best estimate of 979 ÷ 32? (a) 3300 (b) 330 (c) 33
  17. 17.Best estimate of 1425 ÷ 23? (a) 71 (b) 7100 (c) 710
  18. 18.Best estimate of 2559 ÷ 61? (a) 43 (b) 430 (c) 4300
  19. 19.√20 to 1 decimal place? (a) 4.4 (b) 4.3 (c) 4.6 (d) 4.5
  20. 20.√66 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 8.1 (d) 8.2
  21. 21.Best estimate of 2440 ÷ 83? (a) 31 (b) 310 (c) 3100
  22. 22.Best estimate of 6712 ÷ 82? (a) 84 (b) 8400 (c) 840
  23. 23.√53 to 1 decimal place? (a) 7.4 (b) 7.1 (c) 7.3 (d) 7.2
  24. 24.Best estimate of 3679 ÷ 41? (a) 920 (b) 9200 (c) 92
  25. 25.√35 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.8 (d) 6.0
  26. 26.Best estimate of 626 ÷ 26? (a) 210 (b) 2100 (c) 21
  27. 27.Best estimate of 4719 ÷ 84? (a) 59 (b) 5900 (c) 590
  28. 28.√63 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 7.9 (d) 8.1
  29. 29.Best estimate of 6312 ÷ 87? (a) 700 (b) 70 (c) 7000
  30. 30.√30 to 1 decimal place? (a) 5.3 (b) 5.5 (c) 5.4 (d) 5.6
  31. 31.Best estimate of 4192 ÷ 49? (a) 84 (b) 840 (c) 8400
  32. 32.√37 to 1 decimal place? (a) 6.3 (b) 6.0 (c) 6.2 (d) 6.1
  33. 33.√96 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.8 (d) 9.7
  34. 34.√88 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.1 (d) 9.3
  35. 35.Best estimate of 2945 ÷ 34? (a) 980 (b) 9800 (c) 98
  36. 36.Best estimate of 2693 ÷ 87? (a) 3000 (b) 300 (c) 30
  37. 37.Best estimate of 829 ÷ 27? (a) 2800 (b) 28 (c) 280
  38. 38.√58 to 1 decimal place? (a) 7.8 (b) 7.5 (c) 7.7 (d) 7.6
  39. 39.Best estimate of 1435 ÷ 26? (a) 48 (b) 480 (c) 4800
  40. 40.√61 to 1 decimal place? (a) 7.5 (b) 7.8 (c) 7.7 (d) 7.6

Answer key

  1. 7.4
  2. 6.9
  3. 78
  4. 76
  5. 9.6
  6. 9.1
  7. 41
  8. 7.1
  9. 23
  10. 9.4
  11. 93
  12. 4.8
  13. 30
  14. 5.3
  15. 27
  16. 33
  17. 71
  18. 43
  19. 4.5
  20. 8.1
  21. 31
  22. 84
  23. 7.3
  24. 92
  25. 5.9
  26. 21
  27. 59
  28. 7.9
  29. 70
  30. 5.5
  31. 84
  32. 6.1
  33. 9.8
  34. 9.4
  35. 98
  36. 30
  37. 28
  38. 7.6
  39. 48
  40. 7.8

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