← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 627 · 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 2489 ÷ 42? (a) 620 (b) 62 (c) 6200
  2. 2.Best estimate of 4187 ÷ 72? (a) 6000 (b) 60 (c) 600
  3. 3.Best estimate of 1240 ÷ 41? (a) 3100 (b) 310 (c) 31
  4. 4.Best estimate of 2911 ÷ 39? (a) 73 (b) 7300 (c) 730
  5. 5.Best estimate of 928 ÷ 32? (a) 31 (b) 310 (c) 3100
  6. 6.Best estimate of 1575 ÷ 62? (a) 2600 (b) 26 (c) 260
  7. 7.Best estimate of 410 ÷ 24? (a) 210 (b) 21 (c) 2100
  8. 8.√46 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 6.7 (d) 6.6
  9. 9.√37 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.0 (d) 6.1
  10. 10.√88 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.5 (d) 9.4
  11. 11.Best estimate of 1139 ÷ 46? (a) 2300 (b) 23 (c) 230
  12. 12.Best estimate of 3002 ÷ 44? (a) 75 (b) 750 (c) 7500
  13. 13.Best estimate of 3030 ÷ 84? (a) 38 (b) 3800 (c) 380
  14. 14.√74 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  15. 15.Best estimate of 3230 ÷ 86? (a) 360 (b) 36 (c) 3600
  16. 16.Best estimate of 3180 ÷ 34? (a) 1060 (b) 106 (c) 10600
  17. 17.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 8.9 (d) 9.0
  18. 18.√65 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.1 (d) 8.0
  19. 19.√35 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 5.8 (d) 6.0
  20. 20.√53 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.2
  21. 21.Best estimate of 4023 ÷ 68? (a) 5700 (b) 57 (c) 570
  22. 22.Best estimate of 2061 ÷ 39? (a) 52 (b) 520 (c) 5200
  23. 23.Best estimate of 1077 ÷ 49? (a) 220 (b) 2200 (c) 22
  24. 24.Best estimate of 3179 ÷ 38? (a) 79 (b) 7900 (c) 790
  25. 25.Best estimate of 4028 ÷ 54? (a) 8100 (b) 810 (c) 81
  26. 26.√72 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  27. 27.√20 to 1 decimal place? (a) 4.5 (b) 4.4 (c) 4.3 (d) 4.2
  28. 28.Best estimate of 1116 ÷ 26? (a) 3700 (b) 370 (c) 37
  29. 29.Best estimate of 2631 ÷ 36? (a) 660 (b) 6600 (c) 66
  30. 30.Best estimate of 1210 ÷ 72? (a) 17 (b) 1700 (c) 170
  31. 31.Best estimate of 4746 ÷ 54? (a) 950 (b) 9500 (c) 95
  32. 32.√79 to 1 decimal place? (a) 8.8 (b) 9.1 (c) 9.0 (d) 8.9
  33. 33.Best estimate of 1268 ÷ 46? (a) 250 (b) 2500 (c) 25
  34. 34.√89 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.5 (d) 9.3
  35. 35.√30 to 1 decimal place? (a) 5.7 (b) 5.8 (c) 5.5 (d) 5.6
  36. 36.Best estimate of 662 ÷ 34? (a) 2200 (b) 220 (c) 22
  37. 37.√67 to 1 decimal place? (a) 8.5 (b) 8.2 (c) 8.3 (d) 8.4
  38. 38.√52 to 1 decimal place? (a) 7.2 (b) 7.0 (c) 6.9 (d) 7.1
  39. 39.Best estimate of 4235 ÷ 54? (a) 85 (b) 850 (c) 8500
  40. 40.√87 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.2 (d) 9.3

Answer key

  1. 62
  2. 60
  3. 31
  4. 73
  5. 31
  6. 26
  7. 21
  8. 6.8
  9. 6.1
  10. 9.4
  11. 23
  12. 75
  13. 38
  14. 8.6
  15. 36
  16. 106
  17. 9.1
  18. 8.1
  19. 5.9
  20. 7.3
  21. 57
  22. 52
  23. 22
  24. 79
  25. 81
  26. 8.5
  27. 4.5
  28. 37
  29. 66
  30. 17
  31. 95
  32. 8.9
  33. 25
  34. 9.4
  35. 5.5
  36. 22
  37. 8.2
  38. 7.2
  39. 85
  40. 9.3

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