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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 117 · 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.√94 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 10.0 (d) 9.8
  2. 2.Best estimate of 2167 ÷ 26? (a) 72 (b) 7200 (c) 720
  3. 3.Best estimate of 5125 ÷ 72? (a) 73 (b) 7300 (c) 730
  4. 4.√74 to 1 decimal place? (a) 8.3 (b) 8.6 (c) 8.4 (d) 8.5
  5. 5.Best estimate of 4444 ÷ 67? (a) 63 (b) 6300 (c) 630
  6. 6.Best estimate of 3633 ÷ 72? (a) 52 (b) 520 (c) 5200
  7. 7.Best estimate of 4824 ÷ 78? (a) 6000 (b) 600 (c) 60
  8. 8.Best estimate of 1229 ÷ 22? (a) 61 (b) 6100 (c) 610
  9. 9.√28 to 1 decimal place? (a) 5.4 (b) 5.1 (c) 5.3 (d) 5.2
  10. 10.√90 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.5 (d) 9.2
  11. 11.√30 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.5 (d) 5.8
  12. 12.√92 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.8 (d) 9.7
  13. 13.√45 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.7 (d) 6.8
  14. 14.Best estimate of 2482 ÷ 29? (a) 83 (b) 8300 (c) 830
  15. 15.Best estimate of 1005 ÷ 83? (a) 130 (b) 1300 (c) 13
  16. 16.Best estimate of 3632 ÷ 68? (a) 52 (b) 5200 (c) 520
  17. 17.Best estimate of 1604 ÷ 52? (a) 3200 (b) 32 (c) 320
  18. 18.√46 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 6.6 (d) 6.7
  19. 19.Best estimate of 953 ÷ 29? (a) 32 (b) 3200 (c) 320
  20. 20.√65 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 8.1 (d) 7.9
  21. 21.Best estimate of 3458 ÷ 61? (a) 580 (b) 58 (c) 5800
  22. 22.Best estimate of 4853 ÷ 66? (a) 6900 (b) 690 (c) 69
  23. 23.√98 to 1 decimal place? (a) 10.0 (b) 9.8 (c) 10.1 (d) 9.9
  24. 24.Best estimate of 1721 ÷ 37? (a) 430 (b) 43 (c) 4300
  25. 25.√69 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.2 (d) 8.3
  26. 26.√75 to 1 decimal place? (a) 8.9 (b) 8.6 (c) 8.7 (d) 8.8
  27. 27.Best estimate of 6723 ÷ 74? (a) 9600 (b) 960 (c) 96
  28. 28.Best estimate of 3834 ÷ 64? (a) 64 (b) 640 (c) 6400
  29. 29.Best estimate of 2328 ÷ 26? (a) 7800 (b) 78 (c) 780
  30. 30.Best estimate of 3612 ÷ 38? (a) 9000 (b) 900 (c) 90
  31. 31.√35 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 5.9
  32. 32.Best estimate of 784 ÷ 42? (a) 2000 (b) 20 (c) 200
  33. 33.Best estimate of 6930 ÷ 76? (a) 870 (b) 87 (c) 8700
  34. 34.Best estimate of 6122 ÷ 86? (a) 680 (b) 6800 (c) 68
  35. 35.√52 to 1 decimal place? (a) 7.3 (b) 7.1 (c) 7.0 (d) 7.2
  36. 36.√37 to 1 decimal place? (a) 5.9 (b) 6.1 (c) 6.0 (d) 6.2
  37. 37.Best estimate of 1236 ÷ 26? (a) 410 (b) 4100 (c) 41
  38. 38.Best estimate of 5627 ÷ 72? (a) 800 (b) 8000 (c) 80
  39. 39.√89 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.5 (d) 9.3
  40. 40.Best estimate of 2180 ÷ 62? (a) 360 (b) 3600 (c) 36

Answer key

  1. 9.7
  2. 72
  3. 73
  4. 8.6
  5. 63
  6. 52
  7. 60
  8. 61
  9. 5.3
  10. 9.5
  11. 5.5
  12. 9.6
  13. 6.7
  14. 83
  15. 13
  16. 52
  17. 32
  18. 6.8
  19. 32
  20. 8.1
  21. 58
  22. 69
  23. 9.9
  24. 43
  25. 8.3
  26. 8.7
  27. 96
  28. 64
  29. 78
  30. 90
  31. 5.9
  32. 20
  33. 87
  34. 68
  35. 7.2
  36. 6.1
  37. 41
  38. 80
  39. 9.4
  40. 36

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