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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 161 · 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.√62 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.0 (d) 7.7
  2. 2.Best estimate of 4109 ÷ 69? (a) 590 (b) 59 (c) 5900
  3. 3.Best estimate of 2020 ÷ 32? (a) 67 (b) 6700 (c) 670
  4. 4.√74 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.7 (d) 8.6
  5. 5.√72 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.5 (d) 8.6
  6. 6.Best estimate of 3866 ÷ 68? (a) 550 (b) 55 (c) 5500
  7. 7.Best estimate of 1793 ÷ 32? (a) 6000 (b) 60 (c) 600
  8. 8.Best estimate of 5042 ÷ 88? (a) 56 (b) 560 (c) 5600
  9. 9.Best estimate of 1596 ÷ 71? (a) 2300 (b) 23 (c) 230
  10. 10.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.2 (d) 6.3
  11. 11.√69 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.3 (d) 8.5
  12. 12.√58 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.7 (d) 7.5
  13. 13.√92 to 1 decimal place? (a) 9.3 (b) 9.6 (c) 9.5 (d) 9.4
  14. 14.√29 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.1 (d) 5.2
  15. 15.Best estimate of 1207 ÷ 24? (a) 600 (b) 6000 (c) 60
  16. 16.Best estimate of 2834 ÷ 34? (a) 940 (b) 9400 (c) 94
  17. 17.Best estimate of 1661 ÷ 42? (a) 4200 (b) 42 (c) 420
  18. 18.Best estimate of 3096 ÷ 34? (a) 10300 (b) 1030 (c) 103
  19. 19.Best estimate of 4578 ÷ 62? (a) 76 (b) 7600 (c) 760
  20. 20.√20 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.4 (d) 4.5
  21. 21.Best estimate of 3267 ÷ 69? (a) 4700 (b) 470 (c) 47
  22. 22.Best estimate of 1547 ÷ 64? (a) 2600 (b) 260 (c) 26
  23. 23.√34 to 1 decimal place? (a) 5.8 (b) 6.1 (c) 6.0 (d) 5.9
  24. 24.Best estimate of 1560 ÷ 46? (a) 310 (b) 3100 (c) 31
  25. 25.Best estimate of 6225 ÷ 81? (a) 780 (b) 78 (c) 7800
  26. 26.√45 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 6.7 (d) 7.0
  27. 27.√65 to 1 decimal place? (a) 8.3 (b) 8.0 (c) 8.1 (d) 8.2
  28. 28.Best estimate of 7665 ÷ 89? (a) 850 (b) 85 (c) 8500
  29. 29.√78 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.8 (d) 8.9
  30. 30.Best estimate of 2295 ÷ 28? (a) 77 (b) 7700 (c) 770
  31. 31.Best estimate of 2902 ÷ 66? (a) 410 (b) 4100 (c) 41
  32. 32.Best estimate of 3236 ÷ 79? (a) 4000 (b) 400 (c) 40
  33. 33.Best estimate of 3876 ÷ 51? (a) 780 (b) 7800 (c) 78
  34. 34.Best estimate of 2052 ÷ 69? (a) 2900 (b) 29 (c) 290
  35. 35.√75 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.8 (d) 8.5
  36. 36.√37 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.1 (d) 6.2
  37. 37.√61 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 8.0 (d) 7.9
  38. 38.Best estimate of 1329 ÷ 66? (a) 1900 (b) 19 (c) 190
  39. 39.√55 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.3 (d) 7.5
  40. 40.Best estimate of 6891 ÷ 72? (a) 98 (b) 980 (c) 9800

Answer key

  1. 7.9
  2. 59
  3. 67
  4. 8.6
  5. 8.5
  6. 55
  7. 60
  8. 56
  9. 23
  10. 6.3
  11. 8.3
  12. 7.6
  13. 9.6
  14. 5.4
  15. 60
  16. 94
  17. 42
  18. 103
  19. 76
  20. 4.5
  21. 47
  22. 26
  23. 5.8
  24. 31
  25. 78
  26. 6.7
  27. 8.1
  28. 85
  29. 8.8
  30. 77
  31. 41
  32. 40
  33. 78
  34. 29
  35. 8.7
  36. 6.1
  37. 7.8
  38. 19
  39. 7.4
  40. 98

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