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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 818 · 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 5905 ÷ 86? (a) 66 (b) 6600 (c) 660
  2. 2.Best estimate of 3254 ÷ 42? (a) 8100 (b) 810 (c) 81
  3. 3.√31 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.8 (d) 5.6
  4. 4.Best estimate of 2644 ÷ 56? (a) 440 (b) 44 (c) 4400
  5. 5.Best estimate of 1774 ÷ 26? (a) 59 (b) 5900 (c) 590
  6. 6.√72 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.3 (d) 8.4
  7. 7.√94 to 1 decimal place? (a) 9.9 (b) 9.6 (c) 9.8 (d) 9.7
  8. 8.Best estimate of 1904 ÷ 59? (a) 32 (b) 3200 (c) 320
  9. 9.√65 to 1 decimal place? (a) 8.1 (b) 7.9 (c) 8.0 (d) 8.2
  10. 10.√40 to 1 decimal place? (a) 6.1 (b) 6.3 (c) 6.2 (d) 6.4
  11. 11.√96 to 1 decimal place? (a) 10.0 (b) 10.1 (c) 9.8 (d) 9.9
  12. 12.√34 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 5.9 (d) 6.1
  13. 13.√82 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 9.2 (d) 9.1
  14. 14.√69 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 8.3 (d) 8.1
  15. 15.Best estimate of 3649 ÷ 46? (a) 730 (b) 73 (c) 7300
  16. 16.Best estimate of 1841 ÷ 66? (a) 2600 (b) 260 (c) 26
  17. 17.Best estimate of 2556 ÷ 57? (a) 43 (b) 430 (c) 4300
  18. 18.√74 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.6 (d) 8.5
  19. 19.√92 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.7 (d) 9.4
  20. 20.Best estimate of 3276 ÷ 74? (a) 470 (b) 4700 (c) 47
  21. 21.Best estimate of 2538 ÷ 56? (a) 42 (b) 4200 (c) 420
  22. 22.Best estimate of 1105 ÷ 67? (a) 16 (b) 1600 (c) 160
  23. 23.√41 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.7 (d) 6.4
  24. 24.√30 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.6 (d) 5.4
  25. 25.√32 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.4 (d) 5.6
  26. 26.Best estimate of 5916 ÷ 87? (a) 66 (b) 660 (c) 6600
  27. 27.Best estimate of 2043 ÷ 34? (a) 6800 (b) 68 (c) 680
  28. 28.Best estimate of 2090 ÷ 58? (a) 35 (b) 3500 (c) 350
  29. 29.√88 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.7 (d) 9.4
  30. 30.Best estimate of 4841 ÷ 66? (a) 6900 (b) 69 (c) 690
  31. 31.Best estimate of 600 ÷ 46? (a) 1200 (b) 12 (c) 120
  32. 32.√47 to 1 decimal place? (a) 7.1 (b) 6.8 (c) 7.0 (d) 6.9
  33. 33.√27 to 1 decimal place? (a) 5.5 (b) 5.2 (c) 5.3 (d) 5.4
  34. 34.Best estimate of 3481 ÷ 53? (a) 7000 (b) 700 (c) 70
  35. 35.Best estimate of 549 ÷ 27? (a) 18 (b) 1800 (c) 180
  36. 36.√89 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.7 (d) 9.5
  37. 37.√67 to 1 decimal place? (a) 8.1 (b) 8.3 (c) 8.4 (d) 8.2
  38. 38.√84 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.5 (d) 9.3
  39. 39.√59 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 8.0 (d) 7.8
  40. 40.Best estimate of 3870 ÷ 58? (a) 650 (b) 6500 (c) 65

Answer key

  1. 66
  2. 81
  3. 5.6
  4. 44
  5. 59
  6. 8.5
  7. 9.7
  8. 32
  9. 8.1
  10. 6.3
  11. 9.8
  12. 5.8
  13. 9.1
  14. 8.3
  15. 73
  16. 26
  17. 43
  18. 8.6
  19. 9.6
  20. 47
  21. 42
  22. 16
  23. 6.4
  24. 5.5
  25. 5.7
  26. 66
  27. 68
  28. 35
  29. 9.4
  30. 69
  31. 12
  32. 6.9
  33. 5.2
  34. 70
  35. 18
  36. 9.4
  37. 8.2
  38. 9.2
  39. 7.7
  40. 65

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