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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 972 · 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 7788 ÷ 84? (a) 97 (b) 9700 (c) 970
  2. 2.Best estimate of 6025 ÷ 89? (a) 67 (b) 6700 (c) 670
  3. 3.√92 to 1 decimal place? (a) 9.7 (b) 9.5 (c) 9.6 (d) 9.8
  4. 4.Best estimate of 3954 ÷ 76? (a) 4900 (b) 490 (c) 49
  5. 5.√89 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.4
  6. 6.Best estimate of 1786 ÷ 31? (a) 60 (b) 600 (c) 6000
  7. 7.Best estimate of 5172 ÷ 56? (a) 8600 (b) 86 (c) 860
  8. 8.Best estimate of 2504 ÷ 61? (a) 4200 (b) 42 (c) 420
  9. 9.Best estimate of 2078 ÷ 31? (a) 690 (b) 6900 (c) 69
  10. 10.Best estimate of 3675 ÷ 69? (a) 53 (b) 5300 (c) 530
  11. 11.√37 to 1 decimal place? (a) 6.1 (b) 5.9 (c) 6.0 (d) 5.8
  12. 12.Best estimate of 1852 ÷ 56? (a) 310 (b) 31 (c) 3100
  13. 13.Best estimate of 542 ÷ 34? (a) 180 (b) 1800 (c) 18
  14. 14.√66 to 1 decimal place? (a) 8.1 (b) 8.3 (c) 8.4 (d) 8.2
  15. 15.Best estimate of 3644 ÷ 52? (a) 73 (b) 730 (c) 7300
  16. 16.Best estimate of 1657 ÷ 23? (a) 8300 (b) 830 (c) 83
  17. 17.Best estimate of 4427 ÷ 64? (a) 74 (b) 740 (c) 7400
  18. 18.√58 to 1 decimal place? (a) 7.5 (b) 7.3 (c) 7.6 (d) 7.4
  19. 19.Best estimate of 1984 ÷ 58? (a) 3300 (b) 330 (c) 33
  20. 20.√82 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.1
  21. 21.Best estimate of 4801 ÷ 52? (a) 9600 (b) 96 (c) 960
  22. 22.√35 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 5.9
  23. 23.Best estimate of 1068 ÷ 26? (a) 3600 (b) 36 (c) 360
  24. 24.Best estimate of 499 ÷ 41? (a) 1200 (b) 120 (c) 12
  25. 25.Best estimate of 5563 ÷ 87? (a) 620 (b) 6200 (c) 62
  26. 26.Best estimate of 3885 ÷ 66? (a) 5600 (b) 56 (c) 560
  27. 27.Best estimate of 2301 ÷ 81? (a) 2900 (b) 290 (c) 29
  28. 28.Best estimate of 3439 ÷ 36? (a) 860 (b) 86 (c) 8600
  29. 29.Best estimate of 1439 ÷ 86? (a) 1600 (b) 160 (c) 16
  30. 30.Best estimate of 6989 ÷ 89? (a) 780 (b) 7800 (c) 78
  31. 31.Best estimate of 1475 ÷ 33? (a) 490 (b) 4900 (c) 49
  32. 32.Best estimate of 814 ÷ 22? (a) 41 (b) 410 (c) 4100
  33. 33.Best estimate of 4063 ÷ 62? (a) 68 (b) 680 (c) 6800
  34. 34.√26 to 1 decimal place? (a) 5.2 (b) 5.0 (c) 5.1 (d) 5.3
  35. 35.Best estimate of 2095 ÷ 88? (a) 230 (b) 2300 (c) 23
  36. 36.√65 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.1 (d) 8.0
  37. 37.√86 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.1
  38. 38.Best estimate of 3430 ÷ 39? (a) 86 (b) 8600 (c) 860
  39. 39.Best estimate of 2514 ÷ 82? (a) 31 (b) 310 (c) 3100
  40. 40.Best estimate of 882 ÷ 41? (a) 2200 (b) 220 (c) 22

Answer key

  1. 97
  2. 67
  3. 9.6
  4. 49
  5. 9.4
  6. 60
  7. 86
  8. 42
  9. 69
  10. 53
  11. 6.1
  12. 31
  13. 18
  14. 8.1
  15. 73
  16. 83
  17. 74
  18. 7.6
  19. 33
  20. 9.1
  21. 96
  22. 5.9
  23. 36
  24. 12
  25. 62
  26. 56
  27. 29
  28. 86
  29. 16
  30. 78
  31. 49
  32. 41
  33. 68
  34. 5.1
  35. 23
  36. 8.1
  37. 9.3
  38. 86
  39. 31
  40. 22

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