← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 647 · 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.√74 to 1 decimal place? (a) 8.6 (b) 8.3 (c) 8.5 (d) 8.4
  2. 2.√34 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.5 (d) 5.6
  3. 3.Best estimate of 4124 ÷ 52? (a) 82 (b) 820 (c) 8200
  4. 4.Best estimate of 1114 ÷ 26? (a) 3700 (b) 37 (c) 370
  5. 5.√69 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.4 (d) 8.6
  6. 6.√32 to 1 decimal place? (a) 5.7 (b) 5.4 (c) 5.5 (d) 5.6
  7. 7.Best estimate of 5928 ÷ 86? (a) 66 (b) 6600 (c) 660
  8. 8.Best estimate of 1463 ÷ 34? (a) 490 (b) 49 (c) 4900
  9. 9.Best estimate of 1039 ÷ 52? (a) 21 (b) 2100 (c) 210
  10. 10.√82 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.1
  11. 11.Best estimate of 856 ÷ 28? (a) 29 (b) 2900 (c) 290
  12. 12.Best estimate of 6089 ÷ 79? (a) 7600 (b) 76 (c) 760
  13. 13.Best estimate of 1048 ÷ 61? (a) 170 (b) 1700 (c) 17
  14. 14.Best estimate of 2584 ÷ 36? (a) 650 (b) 6500 (c) 65
  15. 15.√52 to 1 decimal place? (a) 7.3 (b) 7.1 (c) 7.2 (d) 7.4
  16. 16.√44 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.5 (d) 6.3
  17. 17.Best estimate of 1021 ÷ 46? (a) 200 (b) 2000 (c) 20
  18. 18.Best estimate of 3465 ÷ 73? (a) 50 (b) 5000 (c) 500
  19. 19.Best estimate of 3225 ÷ 62? (a) 5400 (b) 540 (c) 54
  20. 20.Best estimate of 1916 ÷ 68? (a) 2700 (b) 270 (c) 27
  21. 21.Best estimate of 1859 ÷ 82? (a) 23 (b) 230 (c) 2300
  22. 22.Best estimate of 6133 ÷ 69? (a) 8800 (b) 880 (c) 88
  23. 23.Best estimate of 6750 ÷ 84? (a) 840 (b) 8400 (c) 84
  24. 24.√79 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 9.0 (d) 9.1
  25. 25.Best estimate of 5187 ÷ 82? (a) 6500 (b) 65 (c) 650
  26. 26.Best estimate of 1867 ÷ 69? (a) 270 (b) 27 (c) 2700
  27. 27.Best estimate of 5831 ÷ 72? (a) 830 (b) 8300 (c) 83
  28. 28.√65 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.9 (d) 8.1
  29. 29.√77 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 9.0 (d) 8.8
  30. 30.√85 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.3 (d) 9.4
  31. 31.√42 to 1 decimal place? (a) 6.8 (b) 6.5 (c) 6.6 (d) 6.7
  32. 32.√59 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.9 (d) 7.7
  33. 33.√21 to 1 decimal place? (a) 4.6 (b) 4.5 (c) 4.8 (d) 4.7
  34. 34.Best estimate of 4162 ÷ 72? (a) 5900 (b) 590 (c) 59
  35. 35.Best estimate of 1111 ÷ 46? (a) 22 (b) 220 (c) 2200
  36. 36.Best estimate of 1983 ÷ 64? (a) 3300 (b) 330 (c) 33
  37. 37.Best estimate of 1941 ÷ 24? (a) 97 (b) 9700 (c) 970
  38. 38.√46 to 1 decimal place? (a) 7.0 (b) 6.8 (c) 6.7 (d) 6.9
  39. 39.Best estimate of 870 ÷ 32? (a) 29 (b) 2900 (c) 290
  40. 40.√48 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.1 (d) 7.0

Answer key

  1. 8.6
  2. 5.8
  3. 82
  4. 37
  5. 8.3
  6. 5.7
  7. 66
  8. 49
  9. 21
  10. 9.1
  11. 29
  12. 76
  13. 17
  14. 65
  15. 7.2
  16. 6.6
  17. 20
  18. 50
  19. 54
  20. 27
  21. 23
  22. 88
  23. 84
  24. 8.9
  25. 65
  26. 27
  27. 83
  28. 8.1
  29. 8.8
  30. 9.2
  31. 6.5
  32. 7.7
  33. 4.6
  34. 59
  35. 22
  36. 33
  37. 97
  38. 6.8
  39. 29
  40. 6.9

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