← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 866 · 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) 5.0 (b) 4.7 (c) 4.9 (d) 4.8
  2. 2.√20 to 1 decimal place? (a) 4.8 (b) 4.6 (c) 4.7 (d) 4.5
  3. 3.√37 to 1 decimal place? (a) 6.1 (b) 6.3 (c) 6.2 (d) 6.0
  4. 4.√94 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 9.7 (d) 10.0
  5. 5.Best estimate of 3352 ÷ 38? (a) 84 (b) 840 (c) 8400
  6. 6.√40 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 6.3 (d) 6.2
  7. 7.Best estimate of 1644 ÷ 24? (a) 820 (b) 8200 (c) 82
  8. 8.√59 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  9. 9.Best estimate of 2135 ÷ 23? (a) 1070 (b) 10700 (c) 107
  10. 10.Best estimate of 3411 ÷ 72? (a) 4900 (b) 490 (c) 49
  11. 11.√45 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.7 (d) 6.6
  12. 12.√58 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.6 (d) 7.9
  13. 13.Best estimate of 5106 ÷ 87? (a) 57 (b) 570 (c) 5700
  14. 14.Best estimate of 2225 ÷ 42? (a) 560 (b) 56 (c) 5600
  15. 15.Best estimate of 471 ÷ 29? (a) 1600 (b) 160 (c) 16
  16. 16.Best estimate of 2991 ÷ 36? (a) 750 (b) 75 (c) 7500
  17. 17.√31 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.7 (d) 5.4
  18. 18.Best estimate of 1505 ÷ 27? (a) 50 (b) 500 (c) 5000
  19. 19.√28 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.3 (d) 5.2
  20. 20.√65 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.1 (d) 8.2
  21. 21.Best estimate of 1787 ÷ 49? (a) 360 (b) 36 (c) 3600
  22. 22.√66 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 8.1 (d) 8.0
  23. 23.Best estimate of 841 ÷ 49? (a) 170 (b) 1700 (c) 17
  24. 24.Best estimate of 2222 ÷ 74? (a) 3200 (b) 32 (c) 320
  25. 25.Best estimate of 2573 ÷ 44? (a) 64 (b) 6400 (c) 640
  26. 26.√43 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.6 (d) 6.5
  27. 27.√51 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.0 (d) 6.9
  28. 28.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 9.0
  29. 29.√34 to 1 decimal place? (a) 5.7 (b) 5.8 (c) 6.0 (d) 5.9
  30. 30.√42 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.5
  31. 31.Best estimate of 1062 ÷ 87? (a) 1200 (b) 120 (c) 12
  32. 32.Best estimate of 2446 ÷ 37? (a) 61 (b) 6100 (c) 610
  33. 33.Best estimate of 1417 ÷ 24? (a) 710 (b) 71 (c) 7100
  34. 34.Best estimate of 6239 ÷ 69? (a) 890 (b) 89 (c) 8900
  35. 35.Best estimate of 5293 ÷ 66? (a) 7600 (b) 760 (c) 76
  36. 36.Best estimate of 4392 ÷ 46? (a) 8800 (b) 880 (c) 88
  37. 37.√74 to 1 decimal place? (a) 8.7 (b) 8.4 (c) 8.5 (d) 8.6
  38. 38.Best estimate of 1211 ÷ 26? (a) 400 (b) 40 (c) 4000
  39. 39.Best estimate of 3278 ÷ 36? (a) 82 (b) 8200 (c) 820
  40. 40.Best estimate of 2607 ÷ 31? (a) 8700 (b) 87 (c) 870

Answer key

  1. 4.9
  2. 4.5
  3. 6.1
  4. 9.7
  5. 84
  6. 6.3
  7. 82
  8. 7.7
  9. 107
  10. 49
  11. 6.7
  12. 7.6
  13. 57
  14. 56
  15. 16
  16. 75
  17. 5.6
  18. 50
  19. 5.3
  20. 8.1
  21. 36
  22. 8.1
  23. 17
  24. 32
  25. 64
  26. 6.6
  27. 7.1
  28. 8.7
  29. 5.8
  30. 6.5
  31. 12
  32. 61
  33. 71
  34. 89
  35. 76
  36. 88
  37. 8.6
  38. 40
  39. 82
  40. 87

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