← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 420 · 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 5830 ÷ 62? (a) 970 (b) 9700 (c) 97
  2. 2.Best estimate of 1535 ÷ 21? (a) 77 (b) 770 (c) 7700
  3. 3.Best estimate of 2448 ÷ 33? (a) 82 (b) 820 (c) 8200
  4. 4.√80 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.1 (d) 8.8
  5. 5.Best estimate of 4384 ÷ 88? (a) 4900 (b) 49 (c) 490
  6. 6.√45 to 1 decimal place? (a) 6.5 (b) 6.7 (c) 6.8 (d) 6.6
  7. 7.Best estimate of 1586 ÷ 23? (a) 7900 (b) 79 (c) 790
  8. 8.Best estimate of 2361 ÷ 76? (a) 300 (b) 30 (c) 3000
  9. 9.√74 to 1 decimal place? (a) 8.9 (b) 8.6 (c) 8.8 (d) 8.7
  10. 10.√37 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 5.9 (d) 6.2
  11. 11.Best estimate of 492 ÷ 36? (a) 12 (b) 1200 (c) 120
  12. 12.Best estimate of 1219 ÷ 89? (a) 140 (b) 1400 (c) 14
  13. 13.√82 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.4 (d) 9.1
  14. 14.Best estimate of 1800 ÷ 26? (a) 6000 (b) 60 (c) 600
  15. 15.Best estimate of 5434 ÷ 86? (a) 600 (b) 6000 (c) 60
  16. 16.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  17. 17.Best estimate of 1751 ÷ 62? (a) 290 (b) 2900 (c) 29
  18. 18.Best estimate of 6798 ÷ 73? (a) 970 (b) 9700 (c) 97
  19. 19.√53 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.6
  20. 20.Best estimate of 6133 ÷ 72? (a) 880 (b) 88 (c) 8800
  21. 21.√78 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  22. 22.√34 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 6.1
  23. 23.√38 to 1 decimal place? (a) 6.2 (b) 6.1 (c) 6.3 (d) 6.0
  24. 24.Best estimate of 2104 ÷ 81? (a) 26 (b) 260 (c) 2600
  25. 25.Best estimate of 6883 ÷ 86? (a) 76 (b) 7600 (c) 760
  26. 26.√63 to 1 decimal place? (a) 8.1 (b) 7.9 (c) 8.0 (d) 7.8
  27. 27.Best estimate of 1944 ÷ 54? (a) 3900 (b) 39 (c) 390
  28. 28.√44 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.4 (d) 6.6
  29. 29.√98 to 1 decimal place? (a) 10.0 (b) 10.2 (c) 9.9 (d) 10.1
  30. 30.√72 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.6 (d) 8.4
  31. 31.√77 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.8 (d) 8.5
  32. 32.Best estimate of 889 ÷ 28? (a) 300 (b) 3000 (c) 30
  33. 33.√50 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 6.9 (d) 6.8
  34. 34.√22 to 1 decimal place? (a) 4.7 (b) 4.9 (c) 4.8 (d) 4.6
  35. 35.√85 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.0 (d) 8.9
  36. 36.Best estimate of 1010 ÷ 37? (a) 2500 (b) 250 (c) 25
  37. 37.Best estimate of 3313 ÷ 62? (a) 5500 (b) 550 (c) 55
  38. 38.Best estimate of 1275 ÷ 46? (a) 26 (b) 260 (c) 2600
  39. 39.√96 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 9.7 (d) 10.0
  40. 40.√84 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.2 (d) 9.4

Answer key

  1. 97
  2. 77
  3. 82
  4. 8.9
  5. 49
  6. 6.7
  7. 79
  8. 30
  9. 8.6
  10. 6.1
  11. 12
  12. 14
  13. 9.1
  14. 60
  15. 60
  16. 7.8
  17. 29
  18. 97
  19. 7.3
  20. 88
  21. 8.8
  22. 5.8
  23. 6.2
  24. 26
  25. 76
  26. 7.9
  27. 39
  28. 6.6
  29. 9.9
  30. 8.5
  31. 8.8
  32. 30
  33. 7.1
  34. 4.7
  35. 9.2
  36. 25
  37. 55
  38. 26
  39. 9.8
  40. 9.2

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