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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 297 · 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.√40 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.5 (d) 6.3
  2. 2.√75 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.9 (d) 8.7
  3. 3.Best estimate of 656 ÷ 26? (a) 220 (b) 22 (c) 2200
  4. 4.√84 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.5
  5. 5.√89 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.4 (d) 9.5
  6. 6.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 8.9 (d) 9.0
  7. 7.√69 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.0 (d) 8.2
  8. 8.√52 to 1 decimal place? (a) 7.3 (b) 7.5 (c) 7.4 (d) 7.2
  9. 9.Best estimate of 1408 ÷ 37? (a) 3500 (b) 35 (c) 350
  10. 10.Best estimate of 5815 ÷ 86? (a) 650 (b) 65 (c) 6500
  11. 11.√41 to 1 decimal place? (a) 6.1 (b) 6.4 (c) 6.3 (d) 6.2
  12. 12.Best estimate of 1743 ÷ 47? (a) 35 (b) 3500 (c) 350
  13. 13.Best estimate of 2083 ÷ 49? (a) 420 (b) 4200 (c) 42
  14. 14.Best estimate of 6227 ÷ 71? (a) 8900 (b) 890 (c) 89
  15. 15.Best estimate of 1634 ÷ 22? (a) 82 (b) 8200 (c) 820
  16. 16.Best estimate of 729 ÷ 21? (a) 360 (b) 36 (c) 3600
  17. 17.Best estimate of 7905 ÷ 87? (a) 880 (b) 88 (c) 8800
  18. 18.Best estimate of 1486 ÷ 76? (a) 190 (b) 19 (c) 1900
  19. 19.Best estimate of 2003 ÷ 48? (a) 400 (b) 4000 (c) 40
  20. 20.Best estimate of 5785 ÷ 71? (a) 8300 (b) 83 (c) 830
  21. 21.Best estimate of 2077 ÷ 43? (a) 52 (b) 520 (c) 5200
  22. 22.Best estimate of 4664 ÷ 56? (a) 7800 (b) 780 (c) 78
  23. 23.Best estimate of 1082 ÷ 62? (a) 18 (b) 1800 (c) 180
  24. 24.Best estimate of 1934 ÷ 26? (a) 6400 (b) 640 (c) 64
  25. 25.√63 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.9 (d) 7.8
  26. 26.√98 to 1 decimal place? (a) 10.0 (b) 9.8 (c) 9.9 (d) 10.1
  27. 27.Best estimate of 2009 ÷ 37? (a) 5000 (b) 500 (c) 50
  28. 28.√56 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.5 (d) 7.6
  29. 29.Best estimate of 5591 ÷ 61? (a) 9300 (b) 930 (c) 93
  30. 30.Best estimate of 5685 ÷ 83? (a) 7100 (b) 710 (c) 71
  31. 31.√94 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 9.6
  32. 32.√24 to 1 decimal place? (a) 4.9 (b) 4.6 (c) 4.8 (d) 4.7
  33. 33.√71 to 1 decimal place? (a) 8.6 (b) 8.3 (c) 8.4 (d) 8.5
  34. 34.Best estimate of 1440 ÷ 78? (a) 180 (b) 18 (c) 1800
  35. 35.Best estimate of 906 ÷ 22? (a) 4500 (b) 45 (c) 450
  36. 36.√34 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.8 (d) 5.6
  37. 37.Best estimate of 3300 ÷ 53? (a) 660 (b) 66 (c) 6600
  38. 38.Best estimate of 637 ÷ 27? (a) 210 (b) 21 (c) 2100
  39. 39.Best estimate of 3985 ÷ 72? (a) 57 (b) 570 (c) 5700
  40. 40.Best estimate of 1266 ÷ 72? (a) 180 (b) 1800 (c) 18

Answer key

  1. 6.3
  2. 8.7
  3. 22
  4. 9.2
  5. 9.4
  6. 9.1
  7. 8.3
  8. 7.2
  9. 35
  10. 65
  11. 6.4
  12. 35
  13. 42
  14. 89
  15. 82
  16. 36
  17. 88
  18. 19
  19. 40
  20. 83
  21. 52
  22. 78
  23. 18
  24. 64
  25. 7.9
  26. 9.9
  27. 50
  28. 7.5
  29. 93
  30. 71
  31. 9.7
  32. 4.9
  33. 8.4
  34. 18
  35. 45
  36. 5.8
  37. 66
  38. 21
  39. 57
  40. 18

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