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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 125 · 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 7738 ÷ 88? (a) 86 (b) 8600 (c) 860
  2. 2.Best estimate of 3211 ÷ 42? (a) 8000 (b) 800 (c) 80
  3. 3.Best estimate of 1174 ÷ 26? (a) 3900 (b) 390 (c) 39
  4. 4.√37 to 1 decimal place? (a) 6.3 (b) 6.0 (c) 6.1 (d) 6.2
  5. 5.Best estimate of 3727 ÷ 69? (a) 530 (b) 5300 (c) 53
  6. 6.√42 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.7 (d) 6.5
  7. 7.√40 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.3 (d) 6.5
  8. 8.Best estimate of 8243 ÷ 87? (a) 92 (b) 9200 (c) 920
  9. 9.√98 to 1 decimal place? (a) 10.0 (b) 9.8 (c) 9.9 (d) 10.1
  10. 10.Best estimate of 3892 ÷ 61? (a) 65 (b) 6500 (c) 650
  11. 11.Best estimate of 1462 ÷ 26? (a) 490 (b) 4900 (c) 49
  12. 12.Best estimate of 2995 ÷ 32? (a) 1000 (b) 100 (c) 10000
  13. 13.√79 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 9.2
  14. 14.√46 to 1 decimal place? (a) 6.8 (b) 7.0 (c) 6.9 (d) 6.7
  15. 15.Best estimate of 2324 ÷ 34? (a) 770 (b) 7700 (c) 77
  16. 16.√55 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.5 (d) 7.2
  17. 17.Best estimate of 1775 ÷ 24? (a) 890 (b) 8900 (c) 89
  18. 18.Best estimate of 2083 ÷ 53? (a) 4200 (b) 420 (c) 42
  19. 19.Best estimate of 2406 ÷ 48? (a) 480 (b) 48 (c) 4800
  20. 20.Best estimate of 2761 ÷ 86? (a) 310 (b) 3100 (c) 31
  21. 21.Best estimate of 392 ÷ 29? (a) 1300 (b) 130 (c) 13
  22. 22.Best estimate of 4547 ÷ 58? (a) 76 (b) 7600 (c) 760
  23. 23.√85 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.0
  24. 24.√86 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.3 (d) 9.5
  25. 25.Best estimate of 6507 ÷ 81? (a) 810 (b) 81 (c) 8100
  26. 26.√38 to 1 decimal place? (a) 6.0 (b) 6.3 (c) 6.2 (d) 6.1
  27. 27.Best estimate of 1535 ÷ 23? (a) 770 (b) 77 (c) 7700
  28. 28.Best estimate of 1835 ÷ 31? (a) 610 (b) 6100 (c) 61
  29. 29.Best estimate of 4082 ÷ 72? (a) 580 (b) 58 (c) 5800
  30. 30.Best estimate of 3065 ÷ 48? (a) 610 (b) 61 (c) 6100
  31. 31.√75 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.7 (d) 8.8
  32. 32.Best estimate of 2317 ÷ 32? (a) 770 (b) 7700 (c) 77
  33. 33.√84 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.1 (d) 9.0
  34. 34.√34 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.8 (d) 5.7
  35. 35.√94 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.9 (d) 10.0
  36. 36.Best estimate of 1354 ÷ 46? (a) 2700 (b) 27 (c) 270
  37. 37.√71 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.7 (d) 8.4
  38. 38.√50 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 7.1 (d) 6.8
  39. 39.Best estimate of 6811 ÷ 84? (a) 85 (b) 850 (c) 8500
  40. 40.√96 to 1 decimal place? (a) 9.5 (b) 9.7 (c) 9.8 (d) 9.6

Answer key

  1. 86
  2. 80
  3. 39
  4. 6.1
  5. 53
  6. 6.5
  7. 6.3
  8. 92
  9. 9.9
  10. 65
  11. 49
  12. 100
  13. 8.9
  14. 6.8
  15. 77
  16. 7.4
  17. 89
  18. 42
  19. 48
  20. 31
  21. 13
  22. 76
  23. 9.2
  24. 9.3
  25. 81
  26. 6.2
  27. 77
  28. 61
  29. 58
  30. 61
  31. 8.7
  32. 77
  33. 9.2
  34. 5.8
  35. 9.7
  36. 27
  37. 8.4
  38. 7.1
  39. 85
  40. 9.8

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