← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 916 · 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.√24 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 4.7 (d) 5.0
  2. 2.√84 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 9.1 (d) 8.9
  3. 3.Best estimate of 1508 ÷ 28? (a) 5000 (b) 50 (c) 500
  4. 4.Best estimate of 1400 ÷ 48? (a) 2800 (b) 28 (c) 280
  5. 5.√82 to 1 decimal place? (a) 9.3 (b) 9.0 (c) 9.2 (d) 9.1
  6. 6.Best estimate of 430 ÷ 33? (a) 1400 (b) 140 (c) 14
  7. 7.√28 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.1 (d) 5.2
  8. 8.√43 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.3 (d) 6.4
  9. 9.Best estimate of 1709 ÷ 82? (a) 2100 (b) 21 (c) 210
  10. 10.Best estimate of 2186 ÷ 23? (a) 10900 (b) 1090 (c) 109
  11. 11.Best estimate of 6826 ÷ 86? (a) 7600 (b) 760 (c) 76
  12. 12.√51 to 1 decimal place? (a) 7.2 (b) 6.9 (c) 7.1 (d) 7.0
  13. 13.Best estimate of 3914 ÷ 53? (a) 780 (b) 7800 (c) 78
  14. 14.√38 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.2 (d) 6.1
  15. 15.Best estimate of 1436 ÷ 37? (a) 36 (b) 3600 (c) 360
  16. 16.Best estimate of 2442 ÷ 39? (a) 6100 (b) 610 (c) 61
  17. 17.Best estimate of 1600 ÷ 63? (a) 2700 (b) 27 (c) 270
  18. 18.Best estimate of 720 ÷ 42? (a) 18 (b) 180 (c) 1800
  19. 19.√30 to 1 decimal place? (a) 5.7 (b) 5.8 (c) 5.6 (d) 5.5
  20. 20.Best estimate of 2117 ÷ 87? (a) 24 (b) 240 (c) 2400
  21. 21.Best estimate of 1964 ÷ 64? (a) 33 (b) 330 (c) 3300
  22. 22.√55 to 1 decimal place? (a) 7.4 (b) 7.2 (c) 7.5 (d) 7.3
  23. 23.√50 to 1 decimal place? (a) 7.2 (b) 7.0 (c) 7.1 (d) 6.9
  24. 24.Best estimate of 5745 ÷ 68? (a) 820 (b) 82 (c) 8200
  25. 25.√42 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.6 (d) 6.8
  26. 26.√87 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.4 (d) 9.5
  27. 27.Best estimate of 2357 ÷ 74? (a) 3400 (b) 340 (c) 34
  28. 28.Best estimate of 4914 ÷ 61? (a) 820 (b) 82 (c) 8200
  29. 29.√71 to 1 decimal place? (a) 8.2 (b) 8.4 (c) 8.3 (d) 8.5
  30. 30.√40 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.3 (d) 6.4
  31. 31.Best estimate of 828 ÷ 46? (a) 17 (b) 170 (c) 1700
  32. 32.Best estimate of 970 ÷ 54? (a) 1900 (b) 19 (c) 190
  33. 33.Best estimate of 1589 ÷ 28? (a) 53 (b) 5300 (c) 530
  34. 34.Best estimate of 1109 ÷ 21? (a) 550 (b) 55 (c) 5500
  35. 35.√74 to 1 decimal place? (a) 8.6 (b) 8.3 (c) 8.5 (d) 8.4
  36. 36.√79 to 1 decimal place? (a) 8.6 (b) 8.9 (c) 8.7 (d) 8.8
  37. 37.Best estimate of 4662 ÷ 56? (a) 780 (b) 7800 (c) 78
  38. 38.√26 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 5.1 (d) 5.2
  39. 39.√78 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 8.8
  40. 40.Best estimate of 4084 ÷ 51? (a) 82 (b) 820 (c) 8200

Answer key

  1. 4.9
  2. 9.2
  3. 50
  4. 28
  5. 9.1
  6. 14
  7. 5.3
  8. 6.6
  9. 21
  10. 109
  11. 76
  12. 7.1
  13. 78
  14. 6.2
  15. 36
  16. 61
  17. 27
  18. 18
  19. 5.5
  20. 24
  21. 33
  22. 7.4
  23. 7.1
  24. 82
  25. 6.5
  26. 9.3
  27. 34
  28. 82
  29. 8.4
  30. 6.3
  31. 17
  32. 19
  33. 53
  34. 55
  35. 8.6
  36. 8.9
  37. 78
  38. 5.1
  39. 8.8
  40. 82

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