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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 439 · 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.√67 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 7.9 (d) 8.0
  2. 2.√48 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 7.1 (d) 6.8
  3. 3.Best estimate of 1587 ÷ 29? (a) 530 (b) 53 (c) 5300
  4. 4.Best estimate of 3005 ÷ 48? (a) 6000 (b) 600 (c) 60
  5. 5.Best estimate of 2008 ÷ 67? (a) 2900 (b) 290 (c) 29
  6. 6.Best estimate of 1632 ÷ 24? (a) 82 (b) 8200 (c) 820
  7. 7.Best estimate of 633 ÷ 21? (a) 320 (b) 3200 (c) 32
  8. 8.Best estimate of 1912 ÷ 33? (a) 64 (b) 6400 (c) 640
  9. 9.√87 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.1 (d) 9.4
  10. 10.Best estimate of 2566 ÷ 78? (a) 320 (b) 3200 (c) 32
  11. 11.√94 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 10.0 (d) 9.8
  12. 12.√72 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.3 (d) 8.4
  13. 13.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.0
  14. 14.Best estimate of 1225 ÷ 69? (a) 18 (b) 1800 (c) 180
  15. 15.√23 to 1 decimal place? (a) 4.8 (b) 4.7 (c) 5.0 (d) 4.9
  16. 16.Best estimate of 4970 ÷ 56? (a) 83 (b) 8300 (c) 830
  17. 17.Best estimate of 1922 ÷ 86? (a) 210 (b) 21 (c) 2100
  18. 18.Best estimate of 695 ÷ 32? (a) 23 (b) 2300 (c) 230
  19. 19.√30 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.6 (d) 5.5
  20. 20.√74 to 1 decimal place? (a) 8.7 (b) 8.4 (c) 8.5 (d) 8.6
  21. 21.√29 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.2 (d) 5.4
  22. 22.Best estimate of 2036 ÷ 47? (a) 410 (b) 4100 (c) 41
  23. 23.Best estimate of 2695 ÷ 82? (a) 34 (b) 340 (c) 3400
  24. 24.Best estimate of 3530 ÷ 89? (a) 390 (b) 3900 (c) 39
  25. 25.√22 to 1 decimal place? (a) 4.6 (b) 4.5 (c) 4.7 (d) 4.8
  26. 26.√34 to 1 decimal place? (a) 5.9 (b) 6.1 (c) 5.8 (d) 6.0
  27. 27.Best estimate of 4244 ÷ 78? (a) 5300 (b) 530 (c) 53
  28. 28.Best estimate of 1568 ÷ 27? (a) 52 (b) 520 (c) 5200
  29. 29.√42 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.3 (d) 6.5
  30. 30.√24 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 5.0 (d) 5.1
  31. 31.√32 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 5.8 (d) 5.7
  32. 32.Best estimate of 1581 ÷ 43? (a) 4000 (b) 40 (c) 400
  33. 33.Best estimate of 2223 ÷ 74? (a) 32 (b) 320 (c) 3200
  34. 34.Best estimate of 1097 ÷ 34? (a) 37 (b) 370 (c) 3700
  35. 35.Best estimate of 3488 ÷ 42? (a) 8700 (b) 870 (c) 87
  36. 36.Best estimate of 892 ÷ 32? (a) 300 (b) 30 (c) 3000
  37. 37.Best estimate of 1598 ÷ 82? (a) 2000 (b) 200 (c) 20
  38. 38.Best estimate of 1839 ÷ 34? (a) 610 (b) 61 (c) 6100
  39. 39.Best estimate of 7844 ÷ 87? (a) 87 (b) 8700 (c) 870
  40. 40.Best estimate of 5302 ÷ 89? (a) 5900 (b) 59 (c) 590

Answer key

  1. 8.2
  2. 6.9
  3. 53
  4. 60
  5. 29
  6. 82
  7. 32
  8. 64
  9. 9.3
  10. 32
  11. 9.7
  12. 8.5
  13. 8.1
  14. 18
  15. 4.8
  16. 83
  17. 21
  18. 23
  19. 5.5
  20. 8.6
  21. 5.4
  22. 41
  23. 34
  24. 39
  25. 4.7
  26. 5.8
  27. 53
  28. 52
  29. 6.5
  30. 4.9
  31. 5.7
  32. 40
  33. 32
  34. 37
  35. 87
  36. 30
  37. 20
  38. 61
  39. 87
  40. 59

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