← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 813 · 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.√50 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.3 (d) 7.0
  2. 2.√20 to 1 decimal place? (a) 4.2 (b) 4.4 (c) 4.5 (d) 4.3
  3. 3.√43 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.5 (d) 6.8
  4. 4.√82 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.1 (d) 9.3
  5. 5.√31 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.8 (d) 5.9
  6. 6.Best estimate of 6337 ÷ 81? (a) 790 (b) 79 (c) 7900
  7. 7.√69 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.3 (d) 8.2
  8. 8.√94 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.8 (d) 9.7
  9. 9.Best estimate of 2580 ÷ 28? (a) 860 (b) 8600 (c) 86
  10. 10.Best estimate of 5042 ÷ 61? (a) 840 (b) 84 (c) 8400
  11. 11.√90 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.5 (d) 9.7
  12. 12.√61 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.8 (d) 7.6
  13. 13.Best estimate of 1736 ÷ 31? (a) 5800 (b) 580 (c) 58
  14. 14.√65 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 8.1 (d) 7.9
  15. 15.Best estimate of 5135 ÷ 56? (a) 8600 (b) 86 (c) 860
  16. 16.Best estimate of 1546 ÷ 34? (a) 520 (b) 5200 (c) 52
  17. 17.Best estimate of 2699 ÷ 84? (a) 340 (b) 34 (c) 3400
  18. 18.Best estimate of 1835 ÷ 81? (a) 230 (b) 2300 (c) 23
  19. 19.√66 to 1 decimal place? (a) 7.8 (b) 8.1 (c) 8.0 (d) 7.9
  20. 20.Best estimate of 4016 ÷ 51? (a) 8000 (b) 800 (c) 80
  21. 21.√75 to 1 decimal place? (a) 9.0 (b) 8.7 (c) 8.9 (d) 8.8
  22. 22.Best estimate of 1671 ÷ 86? (a) 190 (b) 1900 (c) 19
  23. 23.Best estimate of 630 ÷ 32? (a) 2100 (b) 21 (c) 210
  24. 24.√56 to 1 decimal place? (a) 7.5 (b) 7.2 (c) 7.3 (d) 7.4
  25. 25.√80 to 1 decimal place? (a) 8.8 (b) 9.0 (c) 8.7 (d) 8.9
  26. 26.√52 to 1 decimal place? (a) 6.9 (b) 7.1 (c) 7.0 (d) 7.2
  27. 27.Best estimate of 1910 ÷ 41? (a) 4800 (b) 480 (c) 48
  28. 28.√86 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.5 (d) 9.2
  29. 29.Best estimate of 917 ÷ 26? (a) 310 (b) 31 (c) 3100
  30. 30.Best estimate of 5304 ÷ 58? (a) 88 (b) 880 (c) 8800
  31. 31.√96 to 1 decimal place? (a) 9.5 (b) 9.8 (c) 9.7 (d) 9.6
  32. 32.Best estimate of 2863 ÷ 82? (a) 3600 (b) 36 (c) 360
  33. 33.√41 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.5 (d) 6.4
  34. 34.Best estimate of 5350 ÷ 59? (a) 890 (b) 8900 (c) 89
  35. 35.Best estimate of 3716 ÷ 81? (a) 460 (b) 46 (c) 4600
  36. 36.Best estimate of 3077 ÷ 46? (a) 62 (b) 6200 (c) 620
  37. 37.Best estimate of 652 ÷ 21? (a) 33 (b) 330 (c) 3300
  38. 38.Best estimate of 7946 ÷ 87? (a) 880 (b) 88 (c) 8800
  39. 39.Best estimate of 1583 ÷ 83? (a) 2000 (b) 200 (c) 20
  40. 40.Best estimate of 2055 ÷ 26? (a) 6900 (b) 690 (c) 69

Answer key

  1. 7.1
  2. 4.5
  3. 6.6
  4. 9.1
  5. 5.6
  6. 79
  7. 8.3
  8. 9.7
  9. 86
  10. 84
  11. 9.5
  12. 7.8
  13. 58
  14. 8.1
  15. 86
  16. 52
  17. 34
  18. 23
  19. 8.1
  20. 80
  21. 8.7
  22. 19
  23. 21
  24. 7.5
  25. 8.9
  26. 7.2
  27. 48
  28. 9.3
  29. 31
  30. 88
  31. 9.8
  32. 36
  33. 6.4
  34. 89
  35. 46
  36. 62
  37. 33
  38. 88
  39. 20
  40. 69

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