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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 935 · 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.√50 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 7.3 (d) 7.2
  2. 2.Best estimate of 2047 ÷ 87? (a) 2300 (b) 230 (c) 23
  3. 3.√42 to 1 decimal place? (a) 6.4 (b) 6.7 (c) 6.5 (d) 6.6
  4. 4.√82 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.4 (d) 9.2
  5. 5.Best estimate of 1015 ÷ 52? (a) 20 (b) 2000 (c) 200
  6. 6.Best estimate of 4872 ÷ 82? (a) 610 (b) 61 (c) 6100
  7. 7.√52 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.5 (d) 7.2
  8. 8.Best estimate of 785 ÷ 33? (a) 260 (b) 26 (c) 2600
  9. 9.Best estimate of 2527 ÷ 32? (a) 840 (b) 8400 (c) 84
  10. 10.√26 to 1 decimal place? (a) 5.1 (b) 5.4 (c) 5.2 (d) 5.3
  11. 11.Best estimate of 5010 ÷ 62? (a) 84 (b) 8400 (c) 840
  12. 12.Best estimate of 2641 ÷ 57? (a) 4400 (b) 44 (c) 440
  13. 13.Best estimate of 2284 ÷ 77? (a) 290 (b) 29 (c) 2900
  14. 14.√43 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 6.7 (d) 6.6
  15. 15.Best estimate of 3997 ÷ 82? (a) 50 (b) 500 (c) 5000
  16. 16.√31 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 5.6 (d) 5.7
  17. 17.Best estimate of 2406 ÷ 51? (a) 480 (b) 4800 (c) 48
  18. 18.√66 to 1 decimal place? (a) 8.2 (b) 8.4 (c) 8.1 (d) 8.3
  19. 19.Best estimate of 2919 ÷ 56? (a) 490 (b) 49 (c) 4900
  20. 20.√40 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.3 (d) 6.1
  21. 21.√90 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.7 (d) 9.5
  22. 22.Best estimate of 5822 ÷ 72? (a) 830 (b) 83 (c) 8300
  23. 23.√21 to 1 decimal place? (a) 4.7 (b) 4.4 (c) 4.6 (d) 4.5
  24. 24.√78 to 1 decimal place? (a) 8.8 (b) 8.9 (c) 9.0 (d) 8.7
  25. 25.Best estimate of 4248 ÷ 71? (a) 610 (b) 61 (c) 6100
  26. 26.√41 to 1 decimal place? (a) 6.1 (b) 6.3 (c) 6.2 (d) 6.4
  27. 27.Best estimate of 382 ÷ 23? (a) 190 (b) 1900 (c) 19
  28. 28.Best estimate of 1785 ÷ 89? (a) 2000 (b) 200 (c) 20
  29. 29.√37 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.1 (d) 5.8
  30. 30.√34 to 1 decimal place? (a) 6.0 (b) 5.7 (c) 5.9 (d) 5.8
  31. 31.Best estimate of 2914 ÷ 52? (a) 580 (b) 5800 (c) 58
  32. 32.√70 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.4 (d) 8.2
  33. 33.Best estimate of 3290 ÷ 89? (a) 3700 (b) 370 (c) 37
  34. 34.Best estimate of 2183 ÷ 29? (a) 7300 (b) 730 (c) 73
  35. 35.√94 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.8 (d) 10.0
  36. 36.√45 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.4 (d) 6.7
  37. 37.√24 to 1 decimal place? (a) 4.9 (b) 5.1 (c) 5.0 (d) 5.2
  38. 38.√32 to 1 decimal place? (a) 5.6 (b) 5.8 (c) 5.5 (d) 5.7
  39. 39.√59 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.6 (d) 7.9
  40. 40.Best estimate of 6964 ÷ 86? (a) 770 (b) 7700 (c) 77

Answer key

  1. 7.1
  2. 23
  3. 6.5
  4. 9.1
  5. 20
  6. 61
  7. 7.2
  8. 26
  9. 84
  10. 5.1
  11. 84
  12. 44
  13. 29
  14. 6.6
  15. 50
  16. 5.6
  17. 48
  18. 8.1
  19. 49
  20. 6.3
  21. 9.5
  22. 83
  23. 4.6
  24. 8.8
  25. 61
  26. 6.4
  27. 19
  28. 20
  29. 6.1
  30. 5.8
  31. 58
  32. 8.4
  33. 37
  34. 73
  35. 9.7
  36. 6.7
  37. 4.9
  38. 5.7
  39. 7.7
  40. 77

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