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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 44 · 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 2548 ÷ 29? (a) 8500 (b) 85 (c) 850
  2. 2.√83 to 1 decimal place? (a) 8.8 (b) 9.1 (c) 9.0 (d) 8.9
  3. 3.Best estimate of 1749 ÷ 31? (a) 58 (b) 5800 (c) 580
  4. 4.Best estimate of 1457 ÷ 71? (a) 210 (b) 2100 (c) 21
  5. 5.Best estimate of 3198 ÷ 63? (a) 530 (b) 5300 (c) 53
  6. 6.Best estimate of 6870 ÷ 77? (a) 86 (b) 860 (c) 8600
  7. 7.√67 to 1 decimal place? (a) 8.2 (b) 8.4 (c) 8.1 (d) 8.3
  8. 8.Best estimate of 4232 ÷ 82? (a) 5300 (b) 53 (c) 530
  9. 9.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.4 (d) 9.3
  10. 10.√74 to 1 decimal place? (a) 8.9 (b) 8.7 (c) 8.6 (d) 8.8
  11. 11.Best estimate of 4024 ÷ 66? (a) 5700 (b) 570 (c) 57
  12. 12.Best estimate of 7801 ÷ 83? (a) 98 (b) 9800 (c) 980
  13. 13.Best estimate of 981 ÷ 38? (a) 250 (b) 2500 (c) 25
  14. 14.√55 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.5 (d) 7.3
  15. 15.√26 to 1 decimal place? (a) 5.4 (b) 5.1 (c) 5.3 (d) 5.2
  16. 16.√58 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.5 (d) 7.4
  17. 17.√50 to 1 decimal place? (a) 7.1 (b) 7.4 (c) 7.2 (d) 7.3
  18. 18.√71 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.7
  19. 19.Best estimate of 2501 ÷ 77? (a) 310 (b) 3100 (c) 31
  20. 20.√61 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.8 (d) 7.9
  21. 21.Best estimate of 2973 ÷ 82? (a) 3700 (b) 37 (c) 370
  22. 22.√46 to 1 decimal place? (a) 7.0 (b) 6.7 (c) 6.8 (d) 6.9
  23. 23.√32 to 1 decimal place? (a) 5.6 (b) 5.8 (c) 5.7 (d) 5.5
  24. 24.√30 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.3 (d) 5.4
  25. 25.Best estimate of 1644 ÷ 53? (a) 330 (b) 3300 (c) 33
  26. 26.√43 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.9 (d) 6.6
  27. 27.√75 to 1 decimal place? (a) 8.9 (b) 8.6 (c) 8.8 (d) 8.7
  28. 28.√59 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 8.0 (d) 7.9
  29. 29.Best estimate of 1905 ÷ 73? (a) 2700 (b) 27 (c) 270
  30. 30.√34 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.8 (d) 5.6
  31. 31.Best estimate of 2649 ÷ 42? (a) 6600 (b) 66 (c) 660
  32. 32.Best estimate of 2924 ÷ 34? (a) 9700 (b) 97 (c) 970
  33. 33.Best estimate of 1769 ÷ 53? (a) 35 (b) 350 (c) 3500
  34. 34.Best estimate of 777 ÷ 28? (a) 26 (b) 260 (c) 2600
  35. 35.Best estimate of 2498 ÷ 61? (a) 4200 (b) 420 (c) 42
  36. 36.Best estimate of 657 ÷ 41? (a) 1600 (b) 160 (c) 16
  37. 37.√90 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.5 (d) 9.4
  38. 38.Best estimate of 6342 ÷ 76? (a) 790 (b) 7900 (c) 79
  39. 39.Best estimate of 2131 ÷ 72? (a) 3000 (b) 30 (c) 300
  40. 40.√35 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 5.6 (d) 5.7

Answer key

  1. 85
  2. 9.1
  3. 58
  4. 21
  5. 53
  6. 86
  7. 8.2
  8. 53
  9. 9.1
  10. 8.6
  11. 57
  12. 98
  13. 25
  14. 7.4
  15. 5.1
  16. 7.6
  17. 7.1
  18. 8.4
  19. 31
  20. 7.8
  21. 37
  22. 6.8
  23. 5.7
  24. 5.5
  25. 33
  26. 6.6
  27. 8.7
  28. 7.7
  29. 27
  30. 5.8
  31. 66
  32. 97
  33. 35
  34. 26
  35. 42
  36. 16
  37. 9.5
  38. 79
  39. 30
  40. 5.9

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