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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 577 · 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.√92 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.5 (d) 9.4
  2. 2.Best estimate of 1413 ÷ 54? (a) 28 (b) 2800 (c) 280
  3. 3.Best estimate of 1962 ÷ 26? (a) 6500 (b) 65 (c) 650
  4. 4.√87 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.2 (d) 9.4
  5. 5.√78 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.6 (d) 8.5
  6. 6.√56 to 1 decimal place? (a) 7.3 (b) 7.5 (c) 7.2 (d) 7.4
  7. 7.√58 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  8. 8.√43 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.3 (d) 6.4
  9. 9.√22 to 1 decimal place? (a) 5.0 (b) 4.7 (c) 4.9 (d) 4.8
  10. 10.Best estimate of 3094 ÷ 87? (a) 34 (b) 3400 (c) 340
  11. 11.Best estimate of 1866 ÷ 49? (a) 3700 (b) 37 (c) 370
  12. 12.√65 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.2 (d) 8.1
  13. 13.Best estimate of 2942 ÷ 31? (a) 98 (b) 980 (c) 9800
  14. 14.√85 to 1 decimal place? (a) 8.9 (b) 9.1 (c) 9.0 (d) 9.2
  15. 15.Best estimate of 2259 ÷ 82? (a) 28 (b) 2800 (c) 280
  16. 16.Best estimate of 3547 ÷ 64? (a) 5900 (b) 590 (c) 59
  17. 17.√40 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.3 (d) 6.1
  18. 18.√29 to 1 decimal place? (a) 5.2 (b) 5.4 (c) 5.3 (d) 5.5
  19. 19.Best estimate of 579 ÷ 27? (a) 190 (b) 1900 (c) 19
  20. 20.Best estimate of 3607 ÷ 74? (a) 5200 (b) 520 (c) 52
  21. 21.√28 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.1 (d) 5.2
  22. 22.√37 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.3 (d) 6.1
  23. 23.Best estimate of 2020 ÷ 87? (a) 2200 (b) 22 (c) 220
  24. 24.√35 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 6.1 (d) 6.2
  25. 25.Best estimate of 1951 ÷ 59? (a) 330 (b) 3300 (c) 33
  26. 26.Best estimate of 3585 ÷ 74? (a) 510 (b) 51 (c) 5100
  27. 27.√30 to 1 decimal place? (a) 5.6 (b) 5.3 (c) 5.5 (d) 5.4
  28. 28.Best estimate of 986 ÷ 46? (a) 2000 (b) 200 (c) 20
  29. 29.Best estimate of 3363 ÷ 68? (a) 4800 (b) 48 (c) 480
  30. 30.Best estimate of 5333 ÷ 62? (a) 890 (b) 8900 (c) 89
  31. 31.Best estimate of 2878 ÷ 56? (a) 480 (b) 48 (c) 4800
  32. 32.√48 to 1 decimal place? (a) 7.0 (b) 7.2 (c) 7.1 (d) 6.9
  33. 33.Best estimate of 2373 ÷ 39? (a) 590 (b) 5900 (c) 59
  34. 34.Best estimate of 1598 ÷ 44? (a) 400 (b) 4000 (c) 40
  35. 35.√23 to 1 decimal place? (a) 4.8 (b) 5.0 (c) 4.7 (d) 4.9
  36. 36.√80 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 9.0 (d) 9.2
  37. 37.Best estimate of 2256 ÷ 56? (a) 380 (b) 3800 (c) 38
  38. 38.√66 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 7.9 (d) 8.1
  39. 39.Best estimate of 6291 ÷ 86? (a) 700 (b) 70 (c) 7000
  40. 40.Best estimate of 868 ÷ 39? (a) 2200 (b) 220 (c) 22

Answer key

  1. 9.6
  2. 28
  3. 65
  4. 9.3
  5. 8.8
  6. 7.5
  7. 7.6
  8. 6.6
  9. 4.7
  10. 34
  11. 37
  12. 8.1
  13. 98
  14. 9.2
  15. 28
  16. 59
  17. 6.3
  18. 5.4
  19. 19
  20. 52
  21. 5.3
  22. 6.1
  23. 22
  24. 5.9
  25. 33
  26. 51
  27. 5.5
  28. 20
  29. 48
  30. 89
  31. 48
  32. 6.9
  33. 59
  34. 40
  35. 4.8
  36. 8.9
  37. 38
  38. 8.1
  39. 70
  40. 22

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