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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 966 · 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 1125 ÷ 28? (a) 38 (b) 380 (c) 3800
  2. 2.√40 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.2 (d) 6.1
  3. 3.√41 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.1 (d) 6.4
  4. 4.Best estimate of 3105 ÷ 36? (a) 78 (b) 780 (c) 7800
  5. 5.√70 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.4 (d) 8.7
  6. 6.Best estimate of 861 ÷ 56? (a) 140 (b) 1400 (c) 14
  7. 7.Best estimate of 1281 ÷ 66? (a) 1800 (b) 18 (c) 180
  8. 8.Best estimate of 4214 ÷ 68? (a) 60 (b) 6000 (c) 600
  9. 9.Best estimate of 2809 ÷ 71? (a) 4000 (b) 400 (c) 40
  10. 10.√24 to 1 decimal place? (a) 4.9 (b) 5.1 (c) 5.2 (d) 5.0
  11. 11.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.0
  12. 12.√51 to 1 decimal place? (a) 7.2 (b) 7.4 (c) 7.3 (d) 7.1
  13. 13.Best estimate of 4574 ÷ 63? (a) 7600 (b) 760 (c) 76
  14. 14.Best estimate of 461 ÷ 28? (a) 150 (b) 1500 (c) 15
  15. 15.√29 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.2 (d) 5.5
  16. 16.√87 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.0
  17. 17.√53 to 1 decimal place? (a) 7.1 (b) 7.4 (c) 7.2 (d) 7.3
  18. 18.√86 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.3 (d) 9.6
  19. 19.Best estimate of 3826 ÷ 42? (a) 96 (b) 9600 (c) 960
  20. 20.√32 to 1 decimal place? (a) 5.7 (b) 5.4 (c) 5.5 (d) 5.6
  21. 21.Best estimate of 4885 ÷ 74? (a) 7000 (b) 700 (c) 70
  22. 22.Best estimate of 4771 ÷ 76? (a) 600 (b) 60 (c) 6000
  23. 23.√35 to 1 decimal place? (a) 6.0 (b) 6.2 (c) 5.9 (d) 6.1
  24. 24.√66 to 1 decimal place? (a) 8.2 (b) 7.9 (c) 8.1 (d) 8.0
  25. 25.Best estimate of 3080 ÷ 67? (a) 4400 (b) 44 (c) 440
  26. 26.√58 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.6 (d) 7.4
  27. 27.Best estimate of 2215 ÷ 72? (a) 32 (b) 3200 (c) 320
  28. 28.√38 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.4 (d) 6.5
  29. 29.Best estimate of 4551 ÷ 56? (a) 760 (b) 7600 (c) 76
  30. 30.Best estimate of 2331 ÷ 32? (a) 780 (b) 7800 (c) 78
  31. 31.Best estimate of 5243 ÷ 76? (a) 6600 (b) 660 (c) 66
  32. 32.Best estimate of 2565 ÷ 28? (a) 860 (b) 8600 (c) 86
  33. 33.Best estimate of 680 ÷ 26? (a) 230 (b) 2300 (c) 23
  34. 34.√28 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.5 (d) 5.4
  35. 35.Best estimate of 876 ÷ 26? (a) 290 (b) 2900 (c) 29
  36. 36.Best estimate of 3587 ÷ 39? (a) 9000 (b) 90 (c) 900
  37. 37.Best estimate of 4569 ÷ 89? (a) 510 (b) 5100 (c) 51
  38. 38.Best estimate of 5817 ÷ 66? (a) 830 (b) 83 (c) 8300
  39. 39.Best estimate of 1995 ÷ 23? (a) 10000 (b) 1000 (c) 100
  40. 40.Best estimate of 2180 ÷ 26? (a) 7300 (b) 73 (c) 730

Answer key

  1. 38
  2. 6.3
  3. 6.4
  4. 78
  5. 8.4
  6. 14
  7. 18
  8. 60
  9. 40
  10. 4.9
  11. 9.1
  12. 7.1
  13. 76
  14. 15
  15. 5.4
  16. 9.3
  17. 7.3
  18. 9.3
  19. 96
  20. 5.7
  21. 70
  22. 60
  23. 5.9
  24. 8.1
  25. 44
  26. 7.6
  27. 32
  28. 6.2
  29. 76
  30. 78
  31. 66
  32. 86
  33. 23
  34. 5.3
  35. 29
  36. 90
  37. 51
  38. 83
  39. 100
  40. 73

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