← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 885 · 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 377 ÷ 26? (a) 1300 (b) 13 (c) 130
  2. 2.Best estimate of 4082 ÷ 54? (a) 82 (b) 8200 (c) 820
  3. 3.√52 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.2
  4. 4.√86 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.6 (d) 9.3
  5. 5.√20 to 1 decimal place? (a) 4.5 (b) 4.4 (c) 4.6 (d) 4.3
  6. 6.Best estimate of 6327 ÷ 69? (a) 9000 (b) 900 (c) 90
  7. 7.Best estimate of 2863 ÷ 36? (a) 7200 (b) 720 (c) 72
  8. 8.Best estimate of 2497 ÷ 51? (a) 500 (b) 5000 (c) 50
  9. 9.√24 to 1 decimal place? (a) 4.6 (b) 4.7 (c) 4.8 (d) 4.9
  10. 10.√76 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.5
  11. 11.Best estimate of 2160 ÷ 64? (a) 360 (b) 3600 (c) 36
  12. 12.Best estimate of 2366 ÷ 28? (a) 790 (b) 7900 (c) 79
  13. 13.√23 to 1 decimal place? (a) 4.9 (b) 4.8 (c) 4.6 (d) 4.7
  14. 14.Best estimate of 763 ÷ 31? (a) 2500 (b) 250 (c) 25
  15. 15.√82 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 9.1 (d) 8.9
  16. 16.√90 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.4 (d) 9.2
  17. 17.Best estimate of 2419 ÷ 26? (a) 8100 (b) 810 (c) 81
  18. 18.Best estimate of 3174 ÷ 73? (a) 45 (b) 450 (c) 4500
  19. 19.√50 to 1 decimal place? (a) 6.8 (b) 7.0 (c) 6.9 (d) 7.1
  20. 20.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.4
  21. 21.√38 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 5.9 (d) 6.1
  22. 22.√74 to 1 decimal place? (a) 8.8 (b) 8.6 (c) 8.9 (d) 8.7
  23. 23.√48 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 7.2 (d) 7.1
  24. 24.Best estimate of 4594 ÷ 83? (a) 5700 (b) 57 (c) 570
  25. 25.Best estimate of 2032 ÷ 23? (a) 10200 (b) 102 (c) 1020
  26. 26.√44 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.7 (d) 6.8
  27. 27.√80 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.8 (d) 8.9
  28. 28.Best estimate of 733 ÷ 48? (a) 1500 (b) 150 (c) 15
  29. 29.Best estimate of 2062 ÷ 63? (a) 34 (b) 340 (c) 3400
  30. 30.Best estimate of 3855 ÷ 56? (a) 6400 (b) 640 (c) 64
  31. 31.√42 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.4 (d) 6.6
  32. 32.√37 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.3 (d) 6.1
  33. 33.√47 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.8 (d) 6.7
  34. 34.√46 to 1 decimal place? (a) 6.9 (b) 6.7 (c) 6.8 (d) 7.0
  35. 35.√56 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.6 (d) 7.5
  36. 36.Best estimate of 2485 ÷ 39? (a) 62 (b) 620 (c) 6200
  37. 37.√94 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.8 (d) 9.6
  38. 38.√26 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.4 (d) 5.3
  39. 39.Best estimate of 1471 ÷ 49? (a) 290 (b) 29 (c) 2900
  40. 40.Best estimate of 1321 ÷ 36? (a) 3300 (b) 33 (c) 330

Answer key

  1. 13
  2. 82
  3. 7.2
  4. 9.3
  5. 4.5
  6. 90
  7. 72
  8. 50
  9. 4.9
  10. 8.7
  11. 36
  12. 79
  13. 4.8
  14. 25
  15. 9.1
  16. 9.5
  17. 81
  18. 45
  19. 7.1
  20. 8.1
  21. 6.2
  22. 8.6
  23. 6.9
  24. 57
  25. 102
  26. 6.6
  27. 8.9
  28. 15
  29. 34
  30. 64
  31. 6.5
  32. 6.1
  33. 6.9
  34. 6.8
  35. 7.5
  36. 62
  37. 9.7
  38. 5.1
  39. 29
  40. 33

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