← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 454 · 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 3915 ÷ 56? (a) 65 (b) 650 (c) 6500
  2. 2.√48 to 1 decimal place? (a) 7.0 (b) 6.8 (c) 6.9 (d) 6.7
  3. 3.Best estimate of 1136 ÷ 61? (a) 190 (b) 1900 (c) 19
  4. 4.Best estimate of 2552 ÷ 77? (a) 32 (b) 3200 (c) 320
  5. 5.√28 to 1 decimal place? (a) 5.5 (b) 5.2 (c) 5.3 (d) 5.4
  6. 6.Best estimate of 2398 ÷ 72? (a) 34 (b) 3400 (c) 340
  7. 7.Best estimate of 4153 ÷ 54? (a) 83 (b) 8300 (c) 830
  8. 8.Best estimate of 2296 ÷ 72? (a) 3300 (b) 330 (c) 33
  9. 9.√37 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.1 (d) 6.2
  10. 10.√66 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.9 (d) 8.2
  11. 11.√74 to 1 decimal place? (a) 8.9 (b) 8.7 (c) 8.8 (d) 8.6
  12. 12.Best estimate of 7129 ÷ 78? (a) 8900 (b) 89 (c) 890
  13. 13.Best estimate of 3511 ÷ 41? (a) 880 (b) 8800 (c) 88
  14. 14.√88 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.2 (d) 9.4
  15. 15.Best estimate of 1034 ÷ 64? (a) 1700 (b) 170 (c) 17
  16. 16.√85 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 9.2
  17. 17.√92 to 1 decimal place? (a) 9.5 (b) 9.7 (c) 9.6 (d) 9.8
  18. 18.√75 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.4 (d) 8.7
  19. 19.Best estimate of 3150 ÷ 36? (a) 7900 (b) 79 (c) 790
  20. 20.Best estimate of 2165 ÷ 61? (a) 3600 (b) 36 (c) 360
  21. 21.Best estimate of 3211 ÷ 82? (a) 400 (b) 4000 (c) 40
  22. 22.√44 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.6 (d) 6.8
  23. 23.Best estimate of 3097 ÷ 33? (a) 1030 (b) 10300 (c) 103
  24. 24.√26 to 1 decimal place? (a) 5.1 (b) 4.9 (c) 5.0 (d) 5.2
  25. 25.√30 to 1 decimal place? (a) 5.4 (b) 5.7 (c) 5.6 (d) 5.5
  26. 26.Best estimate of 1649 ÷ 38? (a) 41 (b) 4100 (c) 410
  27. 27.Best estimate of 2108 ÷ 37? (a) 5300 (b) 530 (c) 53
  28. 28.Best estimate of 405 ÷ 33? (a) 14 (b) 140 (c) 1400
  29. 29.Best estimate of 1670 ÷ 52? (a) 33 (b) 3300 (c) 330
  30. 30.Best estimate of 859 ÷ 67? (a) 120 (b) 12 (c) 1200
  31. 31.Best estimate of 4151 ÷ 67? (a) 590 (b) 5900 (c) 59
  32. 32.Best estimate of 2372 ÷ 82? (a) 300 (b) 30 (c) 3000
  33. 33.Best estimate of 3620 ÷ 62? (a) 600 (b) 60 (c) 6000
  34. 34.√69 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.4 (d) 8.3
  35. 35.√31 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 5.6 (d) 5.7
  36. 36.Best estimate of 1802 ÷ 24? (a) 900 (b) 9000 (c) 90
  37. 37.Best estimate of 3085 ÷ 39? (a) 77 (b) 770 (c) 7700
  38. 38.Best estimate of 1813 ÷ 87? (a) 200 (b) 20 (c) 2000
  39. 39.Best estimate of 486 ÷ 32? (a) 16 (b) 160 (c) 1600
  40. 40.Best estimate of 2115 ÷ 32? (a) 710 (b) 71 (c) 7100

Answer key

  1. 65
  2. 6.9
  3. 19
  4. 32
  5. 5.3
  6. 34
  7. 83
  8. 33
  9. 6.1
  10. 8.1
  11. 8.6
  12. 89
  13. 88
  14. 9.4
  15. 17
  16. 9.2
  17. 9.6
  18. 8.7
  19. 79
  20. 36
  21. 40
  22. 6.6
  23. 103
  24. 5.1
  25. 5.5
  26. 41
  27. 53
  28. 14
  29. 33
  30. 12
  31. 59
  32. 30
  33. 60
  34. 8.3
  35. 5.6
  36. 90
  37. 77
  38. 20
  39. 16
  40. 71

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