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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 488 · 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.√34 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 5.7
  2. 2.√63 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 7.8
  3. 3.Best estimate of 1256 ÷ 32? (a) 420 (b) 42 (c) 4200
  4. 4.Best estimate of 1612 ÷ 76? (a) 200 (b) 2000 (c) 20
  5. 5.√26 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 4.8 (d) 5.1
  6. 6.√89 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.3 (d) 9.4
  7. 7.Best estimate of 983 ÷ 26? (a) 33 (b) 330 (c) 3300
  8. 8.Best estimate of 813 ÷ 36? (a) 200 (b) 20 (c) 2000
  9. 9.Best estimate of 3801 ÷ 42? (a) 950 (b) 95 (c) 9500
  10. 10.√96 to 1 decimal place? (a) 9.8 (b) 10.0 (c) 9.7 (d) 9.9
  11. 11.√45 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.8 (d) 6.5
  12. 12.√70 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2
  13. 13.Best estimate of 3842 ÷ 52? (a) 7700 (b) 77 (c) 770
  14. 14.√40 to 1 decimal place? (a) 6.4 (b) 6.2 (c) 6.5 (d) 6.3
  15. 15.Best estimate of 5092 ÷ 69? (a) 73 (b) 7300 (c) 730
  16. 16.Best estimate of 1930 ÷ 37? (a) 48 (b) 4800 (c) 480
  17. 17.Best estimate of 1023 ÷ 79? (a) 1300 (b) 130 (c) 13
  18. 18.√82 to 1 decimal place? (a) 9.4 (b) 9.1 (c) 9.2 (d) 9.3
  19. 19.√69 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.6
  20. 20.√55 to 1 decimal place? (a) 7.3 (b) 7.6 (c) 7.4 (d) 7.5
  21. 21.Best estimate of 7700 ÷ 83? (a) 96 (b) 9600 (c) 960
  22. 22.√30 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.3 (d) 5.5
  23. 23.Best estimate of 1841 ÷ 68? (a) 2600 (b) 260 (c) 26
  24. 24.Best estimate of 1504 ÷ 83? (a) 190 (b) 1900 (c) 19
  25. 25.Best estimate of 3849 ÷ 63? (a) 640 (b) 64 (c) 6400
  26. 26.√32 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.9 (d) 5.7
  27. 27.Best estimate of 1593 ÷ 48? (a) 3200 (b) 320 (c) 32
  28. 28.Best estimate of 7086 ÷ 81? (a) 8900 (b) 890 (c) 89
  29. 29.√74 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.5 (d) 8.7
  30. 30.√28 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.2 (d) 5.3
  31. 31.√53 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.3 (d) 7.4
  32. 32.Best estimate of 904 ÷ 32? (a) 30 (b) 3000 (c) 300
  33. 33.Best estimate of 7726 ÷ 82? (a) 9700 (b) 970 (c) 97
  34. 34.√66 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.4 (d) 8.2
  35. 35.Best estimate of 1997 ÷ 67? (a) 2900 (b) 29 (c) 290
  36. 36.√44 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.3 (d) 6.4
  37. 37.Best estimate of 675 ÷ 49? (a) 1400 (b) 14 (c) 140
  38. 38.Best estimate of 4911 ÷ 72? (a) 700 (b) 70 (c) 7000
  39. 39.Best estimate of 6457 ÷ 68? (a) 9200 (b) 92 (c) 920
  40. 40.Best estimate of 2546 ÷ 48? (a) 5100 (b) 510 (c) 51

Answer key

  1. 5.8
  2. 7.9
  3. 42
  4. 20
  5. 5.1
  6. 9.4
  7. 33
  8. 20
  9. 95
  10. 9.8
  11. 6.7
  12. 8.4
  13. 77
  14. 6.3
  15. 73
  16. 48
  17. 13
  18. 9.1
  19. 8.3
  20. 7.4
  21. 96
  22. 5.5
  23. 26
  24. 19
  25. 64
  26. 5.7
  27. 32
  28. 89
  29. 8.6
  30. 5.3
  31. 7.3
  32. 30
  33. 97
  34. 8.1
  35. 29
  36. 6.6
  37. 14
  38. 70
  39. 92
  40. 51

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