← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 251 · 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 2479 ÷ 54? (a) 5000 (b) 500 (c) 50
  2. 2.√82 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.8 (d) 8.9
  3. 3.√26 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.3 (d) 5.4
  4. 4.Best estimate of 593 ÷ 33? (a) 2000 (b) 200 (c) 20
  5. 5.Best estimate of 1401 ÷ 38? (a) 35 (b) 3500 (c) 350
  6. 6.√56 to 1 decimal place? (a) 7.5 (b) 7.3 (c) 7.6 (d) 7.4
  7. 7.√41 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.3 (d) 6.4
  8. 8.Best estimate of 5087 ÷ 77? (a) 64 (b) 6400 (c) 640
  9. 9.Best estimate of 2006 ÷ 29? (a) 67 (b) 670 (c) 6700
  10. 10.√70 to 1 decimal place? (a) 8.2 (b) 8.5 (c) 8.3 (d) 8.4
  11. 11.Best estimate of 3114 ÷ 47? (a) 62 (b) 620 (c) 6200
  12. 12.Best estimate of 1010 ÷ 69? (a) 14 (b) 140 (c) 1400
  13. 13.√62 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.8 (d) 8.1
  14. 14.√87 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.2 (d) 9.4
  15. 15.Best estimate of 976 ÷ 79? (a) 12 (b) 120 (c) 1200
  16. 16.Best estimate of 724 ÷ 32? (a) 2400 (b) 24 (c) 240
  17. 17.Best estimate of 4051 ÷ 43? (a) 10100 (b) 101 (c) 1010
  18. 18.√94 to 1 decimal place? (a) 9.8 (b) 9.5 (c) 9.6 (d) 9.7
  19. 19.Best estimate of 2109 ÷ 64? (a) 3500 (b) 35 (c) 350
  20. 20.√53 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.0 (d) 7.3
  21. 21.Best estimate of 2386 ÷ 53? (a) 480 (b) 48 (c) 4800
  22. 22.Best estimate of 2148 ÷ 56? (a) 360 (b) 36 (c) 3600
  23. 23.√92 to 1 decimal place? (a) 9.5 (b) 9.8 (c) 9.7 (d) 9.6
  24. 24.Best estimate of 5175 ÷ 58? (a) 860 (b) 8600 (c) 86
  25. 25.Best estimate of 5000 ÷ 81? (a) 630 (b) 63 (c) 6300
  26. 26.Best estimate of 2087 ÷ 27? (a) 700 (b) 70 (c) 7000
  27. 27.√65 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.1 (d) 8.3
  28. 28.√27 to 1 decimal place? (a) 5.2 (b) 5.0 (c) 5.1 (d) 5.3
  29. 29.√22 to 1 decimal place? (a) 4.8 (b) 4.6 (c) 4.7 (d) 4.5
  30. 30.Best estimate of 2436 ÷ 51? (a) 49 (b) 4900 (c) 490
  31. 31.Best estimate of 568 ÷ 42? (a) 1400 (b) 14 (c) 140
  32. 32.√31 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.7 (d) 5.6
  33. 33.√89 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.7 (d) 9.5
  34. 34.√55 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.5 (d) 7.7
  35. 35.Best estimate of 910 ÷ 27? (a) 300 (b) 3000 (c) 30
  36. 36.√45 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 6.5 (d) 6.6
  37. 37.√98 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 10.0 (d) 9.9
  38. 38.√77 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.8 (d) 9.1
  39. 39.√67 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.4 (d) 8.2
  40. 40.√48 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.7 (d) 6.8

Answer key

  1. 50
  2. 9.1
  3. 5.1
  4. 20
  5. 35
  6. 7.5
  7. 6.4
  8. 64
  9. 67
  10. 8.4
  11. 62
  12. 14
  13. 7.9
  14. 9.3
  15. 12
  16. 24
  17. 101
  18. 9.7
  19. 35
  20. 7.3
  21. 48
  22. 36
  23. 9.6
  24. 86
  25. 63
  26. 70
  27. 8.1
  28. 5.2
  29. 4.7
  30. 49
  31. 14
  32. 5.6
  33. 9.4
  34. 7.4
  35. 30
  36. 6.7
  37. 9.9
  38. 8.8
  39. 8.2
  40. 6.9

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