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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 58 · 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 3226 ÷ 38? (a) 8100 (b) 81 (c) 810
  2. 2.√86 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.3 (d) 9.4
  3. 3.Best estimate of 1573 ÷ 33? (a) 52 (b) 520 (c) 5200
  4. 4.√58 to 1 decimal place? (a) 7.9 (b) 7.6 (c) 7.8 (d) 7.7
  5. 5.√48 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 7.0 (d) 7.1
  6. 6.√96 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.6 (d) 9.8
  7. 7.√26 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 4.9 (d) 5.2
  8. 8.Best estimate of 1227 ÷ 36? (a) 3100 (b) 310 (c) 31
  9. 9.√69 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.1 (d) 8.3
  10. 10.Best estimate of 542 ÷ 21? (a) 2700 (b) 27 (c) 270
  11. 11.√42 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.2 (d) 6.5
  12. 12.Best estimate of 283 ÷ 23? (a) 140 (b) 1400 (c) 14
  13. 13.√31 to 1 decimal place? (a) 5.4 (b) 5.6 (c) 5.3 (d) 5.5
  14. 14.√66 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.2 (d) 8.0
  15. 15.Best estimate of 3030 ÷ 62? (a) 510 (b) 5100 (c) 51
  16. 16.√37 to 1 decimal place? (a) 6.2 (b) 6.1 (c) 6.4 (d) 6.3
  17. 17.√76 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.7 (d) 8.4
  18. 18.√59 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.5 (d) 7.7
  19. 19.Best estimate of 5163 ÷ 54? (a) 1030 (b) 10300 (c) 103
  20. 20.Best estimate of 4245 ÷ 49? (a) 850 (b) 8500 (c) 85
  21. 21.√55 to 1 decimal place? (a) 7.2 (b) 7.5 (c) 7.3 (d) 7.4
  22. 22.Best estimate of 2058 ÷ 38? (a) 5100 (b) 510 (c) 51
  23. 23.Best estimate of 1565 ÷ 26? (a) 52 (b) 5200 (c) 520
  24. 24.Best estimate of 7157 ÷ 86? (a) 8000 (b) 800 (c) 80
  25. 25.Best estimate of 2359 ÷ 49? (a) 4700 (b) 47 (c) 470
  26. 26.Best estimate of 3070 ÷ 51? (a) 61 (b) 610 (c) 6100
  27. 27.√53 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.3 (d) 7.6
  28. 28.√32 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.6 (d) 5.4
  29. 29.Best estimate of 2325 ÷ 38? (a) 58 (b) 5800 (c) 580
  30. 30.√98 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 10.2 (d) 10.1
  31. 31.Best estimate of 5399 ÷ 63? (a) 9000 (b) 90 (c) 900
  32. 32.Best estimate of 3655 ÷ 42? (a) 910 (b) 91 (c) 9100
  33. 33.Best estimate of 1695 ÷ 44? (a) 42 (b) 4200 (c) 420
  34. 34.Best estimate of 6728 ÷ 89? (a) 7500 (b) 75 (c) 750
  35. 35.Best estimate of 5717 ÷ 61? (a) 9500 (b) 950 (c) 95
  36. 36.√45 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 7.0 (d) 6.8
  37. 37.Best estimate of 1220 ÷ 27? (a) 41 (b) 410 (c) 4100
  38. 38.√34 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 5.9 (d) 5.8
  39. 39.√74 to 1 decimal place? (a) 8.9 (b) 8.7 (c) 8.6 (d) 8.8
  40. 40.Best estimate of 3884 ÷ 46? (a) 780 (b) 7800 (c) 78

Answer key

  1. 81
  2. 9.3
  3. 52
  4. 7.6
  5. 6.9
  6. 9.8
  7. 5.1
  8. 31
  9. 8.3
  10. 27
  11. 6.5
  12. 14
  13. 5.6
  14. 8.1
  15. 51
  16. 6.1
  17. 8.7
  18. 7.7
  19. 103
  20. 85
  21. 7.4
  22. 51
  23. 52
  24. 80
  25. 47
  26. 61
  27. 7.3
  28. 5.7
  29. 58
  30. 9.9
  31. 90
  32. 91
  33. 42
  34. 75
  35. 95
  36. 6.7
  37. 41
  38. 5.8
  39. 8.6
  40. 78

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