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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 561 · 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.√88 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.6 (d) 9.5
  2. 2.√92 to 1 decimal place? (a) 9.5 (b) 9.8 (c) 9.7 (d) 9.6
  3. 3.√37 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.1 (d) 6.2
  4. 4.√98 to 1 decimal place? (a) 10.2 (b) 9.9 (c) 10.0 (d) 10.1
  5. 5.Best estimate of 1528 ÷ 51? (a) 31 (b) 310 (c) 3100
  6. 6.√22 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 4.7
  7. 7.√63 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 7.7 (d) 7.6
  8. 8.Best estimate of 4257 ÷ 58? (a) 7100 (b) 71 (c) 710
  9. 9.√82 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 8.9 (d) 9.1
  10. 10.√94 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.5 (d) 9.7
  11. 11.Best estimate of 2760 ÷ 43? (a) 69 (b) 690 (c) 6900
  12. 12.Best estimate of 1381 ÷ 28? (a) 4600 (b) 46 (c) 460
  13. 13.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  14. 14.Best estimate of 2309 ÷ 84? (a) 29 (b) 290 (c) 2900
  15. 15.√45 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.8 (d) 6.7
  16. 16.Best estimate of 2556 ÷ 49? (a) 510 (b) 51 (c) 5100
  17. 17.√26 to 1 decimal place? (a) 5.0 (b) 5.1 (c) 4.9 (d) 5.2
  18. 18.√96 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.8 (d) 9.6
  19. 19.Best estimate of 2489 ÷ 29? (a) 830 (b) 83 (c) 8300
  20. 20.√35 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 5.7 (d) 5.6
  21. 21.√79 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 9.2 (d) 9.1
  22. 22.Best estimate of 4433 ÷ 56? (a) 740 (b) 74 (c) 7400
  23. 23.Best estimate of 3625 ÷ 73? (a) 520 (b) 5200 (c) 52
  24. 24.Best estimate of 2065 ÷ 58? (a) 3400 (b) 340 (c) 34
  25. 25.√89 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.3 (d) 9.4
  26. 26.√58 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.6 (d) 7.8
  27. 27.Best estimate of 2270 ÷ 38? (a) 5700 (b) 57 (c) 570
  28. 28.√32 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.0 (d) 5.7
  29. 29.Best estimate of 4454 ÷ 86? (a) 490 (b) 4900 (c) 49
  30. 30.√42 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.8 (d) 6.7
  31. 31.Best estimate of 3877 ÷ 51? (a) 78 (b) 7800 (c) 780
  32. 32.Best estimate of 991 ÷ 26? (a) 3300 (b) 330 (c) 33
  33. 33.√50 to 1 decimal place? (a) 7.1 (b) 7.3 (c) 7.0 (d) 7.2
  34. 34.Best estimate of 3133 ÷ 52? (a) 6300 (b) 63 (c) 630
  35. 35.Best estimate of 4812 ÷ 56? (a) 80 (b) 8000 (c) 800
  36. 36.√34 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.8 (d) 5.5
  37. 37.Best estimate of 2009 ÷ 49? (a) 400 (b) 40 (c) 4000
  38. 38.√75 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.8 (d) 8.7
  39. 39.√38 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.1 (d) 6.2
  40. 40.√87 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.4 (d) 9.2

Answer key

  1. 9.4
  2. 9.6
  3. 6.1
  4. 9.9
  5. 31
  6. 4.7
  7. 7.9
  8. 71
  9. 9.1
  10. 9.7
  11. 69
  12. 46
  13. 7.8
  14. 29
  15. 6.7
  16. 51
  17. 5.1
  18. 9.8
  19. 83
  20. 5.9
  21. 8.9
  22. 74
  23. 52
  24. 34
  25. 9.4
  26. 7.6
  27. 57
  28. 5.7
  29. 49
  30. 6.5
  31. 78
  32. 33
  33. 7.1
  34. 63
  35. 80
  36. 5.8
  37. 40
  38. 8.7
  39. 6.2
  40. 9.3

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