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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 845 · 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 2965 ÷ 46? (a) 5900 (b) 590 (c) 59
  2. 2.√96 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 10.1 (d) 9.8
  3. 3.Best estimate of 4038 ÷ 46? (a) 81 (b) 810 (c) 8100
  4. 4.Best estimate of 1541 ÷ 39? (a) 3900 (b) 39 (c) 390
  5. 5.Best estimate of 1032 ÷ 56? (a) 170 (b) 17 (c) 1700
  6. 6.√28 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.2 (d) 5.1
  7. 7.Best estimate of 1850 ÷ 22? (a) 9300 (b) 93 (c) 930
  8. 8.Best estimate of 1780 ÷ 86? (a) 20 (b) 2000 (c) 200
  9. 9.√82 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 9.1 (d) 8.8
  10. 10.√26 to 1 decimal place? (a) 5.1 (b) 4.8 (c) 4.9 (d) 5.0
  11. 11.√86 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 9.2 (d) 9.3
  12. 12.Best estimate of 4944 ÷ 66? (a) 7100 (b) 71 (c) 710
  13. 13.√40 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.3 (d) 6.5
  14. 14.Best estimate of 7835 ÷ 86? (a) 870 (b) 87 (c) 8700
  15. 15.Best estimate of 1596 ÷ 76? (a) 2000 (b) 200 (c) 20
  16. 16.√66 to 1 decimal place? (a) 8.1 (b) 7.9 (c) 7.8 (d) 8.0
  17. 17.√58 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.6 (d) 7.7
  18. 18.Best estimate of 2369 ÷ 58? (a) 39 (b) 3900 (c) 390
  19. 19.Best estimate of 5645 ÷ 62? (a) 9400 (b) 940 (c) 94
  20. 20.√56 to 1 decimal place? (a) 7.7 (b) 7.4 (c) 7.6 (d) 7.5
  21. 21.√69 to 1 decimal place? (a) 8.2 (b) 8.5 (c) 8.4 (d) 8.3
  22. 22.Best estimate of 1623 ÷ 27? (a) 540 (b) 54 (c) 5400
  23. 23.Best estimate of 5073 ÷ 78? (a) 6300 (b) 63 (c) 630
  24. 24.√45 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 7.0
  25. 25.√62 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.6 (d) 7.9
  26. 26.Best estimate of 1687 ÷ 26? (a) 5600 (b) 560 (c) 56
  27. 27.√70 to 1 decimal place? (a) 8.5 (b) 8.7 (c) 8.6 (d) 8.4
  28. 28.Best estimate of 1392 ÷ 41? (a) 350 (b) 3500 (c) 35
  29. 29.Best estimate of 2611 ÷ 56? (a) 440 (b) 4400 (c) 44
  30. 30.Best estimate of 884 ÷ 23? (a) 4400 (b) 440 (c) 44
  31. 31.Best estimate of 3862 ÷ 89? (a) 4300 (b) 43 (c) 430
  32. 32.√77 to 1 decimal place? (a) 8.7 (b) 9.0 (c) 8.9 (d) 8.8
  33. 33.√72 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.4 (d) 8.3
  34. 34.Best estimate of 2024 ÷ 72? (a) 29 (b) 290 (c) 2900
  35. 35.Best estimate of 2158 ÷ 54? (a) 43 (b) 4300 (c) 430
  36. 36.√37 to 1 decimal place? (a) 6.1 (b) 6.3 (c) 6.4 (d) 6.2
  37. 37.Best estimate of 5699 ÷ 71? (a) 810 (b) 8100 (c) 81
  38. 38.√74 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.3 (d) 8.5
  39. 39.Best estimate of 1510 ÷ 26? (a) 5000 (b) 50 (c) 500
  40. 40.Best estimate of 877 ÷ 33? (a) 290 (b) 29 (c) 2900

Answer key

  1. 59
  2. 9.8
  3. 81
  4. 39
  5. 17
  6. 5.3
  7. 93
  8. 20
  9. 9.1
  10. 5.1
  11. 9.3
  12. 71
  13. 6.3
  14. 87
  15. 20
  16. 8.1
  17. 7.6
  18. 39
  19. 94
  20. 7.5
  21. 8.3
  22. 54
  23. 63
  24. 6.7
  25. 7.9
  26. 56
  27. 8.4
  28. 35
  29. 44
  30. 44
  31. 43
  32. 8.8
  33. 8.5
  34. 29
  35. 43
  36. 6.1
  37. 81
  38. 8.6
  39. 50
  40. 29

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