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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 142 · 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 2039 ÷ 79? (a) 2500 (b) 25 (c) 250
  2. 2.√61 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.5 (d) 7.7
  3. 3.√71 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2
  4. 4.√29 to 1 decimal place? (a) 5.5 (b) 5.2 (c) 5.3 (d) 5.4
  5. 5.√48 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.7 (d) 6.8
  6. 6.Best estimate of 876 ÷ 57? (a) 15 (b) 150 (c) 1500
  7. 7.Best estimate of 736 ÷ 41? (a) 18 (b) 1800 (c) 180
  8. 8.√96 to 1 decimal place? (a) 10.0 (b) 9.7 (c) 9.9 (d) 9.8
  9. 9.Best estimate of 1194 ÷ 62? (a) 2000 (b) 200 (c) 20
  10. 10.Best estimate of 3393 ÷ 69? (a) 48 (b) 480 (c) 4800
  11. 11.√76 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.8 (d) 8.7
  12. 12.√46 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.5
  13. 13.√74 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.7 (d) 8.5
  14. 14.√47 to 1 decimal place? (a) 7.0 (b) 6.7 (c) 6.8 (d) 6.9
  15. 15.Best estimate of 1009 ÷ 23? (a) 500 (b) 5000 (c) 50
  16. 16.√82 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 9.1 (d) 8.9
  17. 17.√32 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.4 (d) 5.5
  18. 18.√59 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 8.0 (d) 7.9
  19. 19.√56 to 1 decimal place? (a) 7.5 (b) 7.8 (c) 7.7 (d) 7.6
  20. 20.√89 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.4
  21. 21.√67 to 1 decimal place? (a) 7.9 (b) 8.2 (c) 8.1 (d) 8.0
  22. 22.Best estimate of 626 ÷ 22? (a) 31 (b) 310 (c) 3100
  23. 23.√37 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.1 (d) 6.3
  24. 24.Best estimate of 695 ÷ 31? (a) 23 (b) 230 (c) 2300
  25. 25.√77 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.9 (d) 8.8
  26. 26.√22 to 1 decimal place? (a) 4.8 (b) 4.7 (c) 4.6 (d) 4.5
  27. 27.√63 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.9 (d) 8.2
  28. 28.Best estimate of 583 ÷ 32? (a) 19 (b) 1900 (c) 190
  29. 29.Best estimate of 5785 ÷ 82? (a) 72 (b) 720 (c) 7200
  30. 30.Best estimate of 2427 ÷ 59? (a) 400 (b) 40 (c) 4000
  31. 31.√92 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 9.6
  32. 32.Best estimate of 1180 ÷ 69? (a) 1700 (b) 17 (c) 170
  33. 33.Best estimate of 1536 ÷ 57? (a) 26 (b) 260 (c) 2600
  34. 34.√94 to 1 decimal place? (a) 10.0 (b) 9.8 (c) 9.9 (d) 9.7
  35. 35.√90 to 1 decimal place? (a) 9.2 (b) 9.5 (c) 9.3 (d) 9.4
  36. 36.√86 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 9.3
  37. 37.Best estimate of 3322 ÷ 53? (a) 660 (b) 6600 (c) 66
  38. 38.Best estimate of 1054 ÷ 48? (a) 210 (b) 21 (c) 2100
  39. 39.√42 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.4 (d) 6.6
  40. 40.√40 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.2 (d) 6.5

Answer key

  1. 25
  2. 7.8
  3. 8.4
  4. 5.4
  5. 6.9
  6. 15
  7. 18
  8. 9.8
  9. 20
  10. 48
  11. 8.7
  12. 6.8
  13. 8.6
  14. 6.9
  15. 50
  16. 9.1
  17. 5.7
  18. 7.7
  19. 7.5
  20. 9.4
  21. 8.2
  22. 31
  23. 6.1
  24. 23
  25. 8.8
  26. 4.7
  27. 7.9
  28. 19
  29. 72
  30. 40
  31. 9.6
  32. 17
  33. 26
  34. 9.7
  35. 9.5
  36. 9.3
  37. 66
  38. 21
  39. 6.5
  40. 6.3

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