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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 364 · 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 3286 ÷ 52? (a) 66 (b) 6600 (c) 660
  2. 2.√26 to 1 decimal place? (a) 5.0 (b) 5.1 (c) 5.2 (d) 5.3
  3. 3.√30 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.5 (d) 5.8
  4. 4.√32 to 1 decimal place? (a) 6.0 (b) 5.7 (c) 5.8 (d) 5.9
  5. 5.Best estimate of 3056 ÷ 71? (a) 4400 (b) 440 (c) 44
  6. 6.Best estimate of 4768 ÷ 71? (a) 68 (b) 680 (c) 6800
  7. 7.Best estimate of 822 ÷ 23? (a) 410 (b) 4100 (c) 41
  8. 8.√37 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 5.9 (d) 5.8
  9. 9.Best estimate of 6544 ÷ 76? (a) 8200 (b) 82 (c) 820
  10. 10.√69 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.2 (d) 8.4
  11. 11.Best estimate of 3922 ÷ 73? (a) 560 (b) 56 (c) 5600
  12. 12.Best estimate of 750 ÷ 34? (a) 250 (b) 2500 (c) 25
  13. 13.Best estimate of 1724 ÷ 33? (a) 570 (b) 5700 (c) 57
  14. 14.Best estimate of 844 ÷ 56? (a) 14 (b) 140 (c) 1400
  15. 15.Best estimate of 4270 ÷ 78? (a) 530 (b) 53 (c) 5300
  16. 16.√86 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.5
  17. 17.Best estimate of 5406 ÷ 74? (a) 7700 (b) 770 (c) 77
  18. 18.Best estimate of 4798 ÷ 54? (a) 96 (b) 9600 (c) 960
  19. 19.√83 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.2 (d) 9.1
  20. 20.√50 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.0 (d) 7.3
  21. 21.Best estimate of 1115 ÷ 52? (a) 22 (b) 220 (c) 2200
  22. 22.√45 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.7 (d) 6.9
  23. 23.Best estimate of 6112 ÷ 86? (a) 680 (b) 68 (c) 6800
  24. 24.Best estimate of 1677 ÷ 52? (a) 34 (b) 3400 (c) 340
  25. 25.Best estimate of 2433 ÷ 37? (a) 6100 (b) 610 (c) 61
  26. 26.Best estimate of 2494 ÷ 62? (a) 4200 (b) 420 (c) 42
  27. 27.√92 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.7 (d) 9.9
  28. 28.Best estimate of 4093 ÷ 51? (a) 8200 (b) 82 (c) 820
  29. 29.√85 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.0 (d) 9.1
  30. 30.√41 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.5 (d) 6.3
  31. 31.√61 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.8 (d) 7.9
  32. 32.√96 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.8 (d) 10.1
  33. 33.Best estimate of 8138 ÷ 88? (a) 9000 (b) 900 (c) 90
  34. 34.Best estimate of 2631 ÷ 47? (a) 530 (b) 5300 (c) 53
  35. 35.√29 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.3 (d) 5.1
  36. 36.√82 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.1
  37. 37.√55 to 1 decimal place? (a) 7.4 (b) 7.2 (c) 7.1 (d) 7.3
  38. 38.Best estimate of 4575 ÷ 77? (a) 57 (b) 570 (c) 5700
  39. 39.Best estimate of 1666 ÷ 42? (a) 4200 (b) 42 (c) 420
  40. 40.Best estimate of 4627 ÷ 71? (a) 6600 (b) 66 (c) 660

Answer key

  1. 66
  2. 5.1
  3. 5.5
  4. 5.7
  5. 44
  6. 68
  7. 41
  8. 6.1
  9. 82
  10. 8.3
  11. 56
  12. 25
  13. 57
  14. 14
  15. 53
  16. 9.3
  17. 77
  18. 96
  19. 9.1
  20. 7.1
  21. 22
  22. 6.7
  23. 68
  24. 34
  25. 61
  26. 42
  27. 9.6
  28. 82
  29. 9.2
  30. 6.4
  31. 7.8
  32. 9.8
  33. 90
  34. 53
  35. 5.4
  36. 9.1
  37. 7.4
  38. 57
  39. 42
  40. 66

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