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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 861 · 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 1446 ÷ 43? (a) 3600 (b) 36 (c) 360
  2. 2.Best estimate of 1705 ÷ 36? (a) 430 (b) 43 (c) 4300
  3. 3.Best estimate of 774 ÷ 39? (a) 19 (b) 1900 (c) 190
  4. 4.√27 to 1 decimal place? (a) 5.3 (b) 5.0 (c) 5.1 (d) 5.2
  5. 5.√47 to 1 decimal place? (a) 7.1 (b) 6.8 (c) 6.9 (d) 7.0
  6. 6.√76 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.7 (d) 8.5
  7. 7.Best estimate of 1060 ÷ 42? (a) 2700 (b) 27 (c) 270
  8. 8.Best estimate of 6379 ÷ 89? (a) 7100 (b) 71 (c) 710
  9. 9.Best estimate of 2860 ÷ 44? (a) 720 (b) 72 (c) 7200
  10. 10.√75 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.8 (d) 8.6
  11. 11.√85 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.5 (d) 9.3
  12. 12.Best estimate of 3540 ÷ 84? (a) 44 (b) 4400 (c) 440
  13. 13.Best estimate of 3569 ÷ 61? (a) 5900 (b) 59 (c) 590
  14. 14.Best estimate of 4716 ÷ 71? (a) 670 (b) 67 (c) 6700
  15. 15.√65 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2
  16. 16.√37 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 6.3 (d) 6.2
  17. 17.Best estimate of 4725 ÷ 84? (a) 590 (b) 5900 (c) 59
  18. 18.Best estimate of 1730 ÷ 57? (a) 29 (b) 2900 (c) 290
  19. 19.√21 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.8 (d) 4.5
  20. 20.√89 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.5 (d) 9.3
  21. 21.Best estimate of 5269 ÷ 76? (a) 6600 (b) 660 (c) 66
  22. 22.Best estimate of 3980 ÷ 57? (a) 660 (b) 6600 (c) 66
  23. 23.Best estimate of 1626 ÷ 24? (a) 810 (b) 8100 (c) 81
  24. 24.Best estimate of 652 ÷ 27? (a) 22 (b) 220 (c) 2200
  25. 25.√29 to 1 decimal place? (a) 5.3 (b) 5.6 (c) 5.4 (d) 5.5
  26. 26.Best estimate of 2614 ÷ 29? (a) 8700 (b) 87 (c) 870
  27. 27.Best estimate of 1719 ÷ 71? (a) 2500 (b) 25 (c) 250
  28. 28.√90 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.4 (d) 9.6
  29. 29.√82 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.1 (d) 9.2
  30. 30.Best estimate of 1523 ÷ 68? (a) 22 (b) 2200 (c) 220
  31. 31.√96 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 10.1 (d) 9.8
  32. 32.Best estimate of 871 ÷ 71? (a) 1200 (b) 12 (c) 120
  33. 33.Best estimate of 5914 ÷ 67? (a) 8400 (b) 840 (c) 84
  34. 34.Best estimate of 2159 ÷ 26? (a) 7200 (b) 72 (c) 720
  35. 35.√55 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.7 (d) 7.5
  36. 36.Best estimate of 3579 ÷ 62? (a) 6000 (b) 60 (c) 600
  37. 37.√98 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.7 (d) 9.8
  38. 38.√71 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.5 (d) 8.7
  39. 39.√58 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.5 (d) 7.6
  40. 40.Best estimate of 2080 ÷ 56? (a) 350 (b) 3500 (c) 35

Answer key

  1. 36
  2. 43
  3. 19
  4. 5.2
  5. 6.9
  6. 8.7
  7. 27
  8. 71
  9. 72
  10. 8.7
  11. 9.2
  12. 44
  13. 59
  14. 67
  15. 8.1
  16. 6.1
  17. 59
  18. 29
  19. 4.6
  20. 9.4
  21. 66
  22. 66
  23. 81
  24. 22
  25. 5.4
  26. 87
  27. 25
  28. 9.5
  29. 9.1
  30. 22
  31. 9.8
  32. 12
  33. 84
  34. 72
  35. 7.4
  36. 60
  37. 9.9
  38. 8.4
  39. 7.6
  40. 35

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