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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 245 · 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.√23 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 4.7
  2. 2.Best estimate of 4033 ÷ 88? (a) 4500 (b) 450 (c) 45
  3. 3.Best estimate of 1177 ÷ 81? (a) 1500 (b) 150 (c) 15
  4. 4.Best estimate of 3149 ÷ 36? (a) 7900 (b) 790 (c) 79
  5. 5.Best estimate of 2438 ÷ 38? (a) 610 (b) 61 (c) 6100
  6. 6.Best estimate of 849 ÷ 42? (a) 210 (b) 2100 (c) 21
  7. 7.Best estimate of 1852 ÷ 56? (a) 310 (b) 3100 (c) 31
  8. 8.Best estimate of 3786 ÷ 48? (a) 76 (b) 7600 (c) 760
  9. 9.√40 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.5 (d) 6.4
  10. 10.√74 to 1 decimal place? (a) 8.8 (b) 8.6 (c) 8.5 (d) 8.7
  11. 11.√63 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.2 (d) 8.1
  12. 12.Best estimate of 4117 ÷ 52? (a) 82 (b) 8200 (c) 820
  13. 13.√55 to 1 decimal place? (a) 7.4 (b) 7.2 (c) 7.3 (d) 7.5
  14. 14.Best estimate of 2632 ÷ 38? (a) 660 (b) 66 (c) 6600
  15. 15.Best estimate of 3692 ÷ 67? (a) 53 (b) 5300 (c) 530
  16. 16.√50 to 1 decimal place? (a) 7.2 (b) 6.9 (c) 7.1 (d) 7.0
  17. 17.Best estimate of 3340 ÷ 68? (a) 48 (b) 480 (c) 4800
  18. 18.Best estimate of 4447 ÷ 76? (a) 56 (b) 5600 (c) 560
  19. 19.√94 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.8 (d) 9.7
  20. 20.Best estimate of 1011 ÷ 33? (a) 34 (b) 340 (c) 3400
  21. 21.Best estimate of 3636 ÷ 66? (a) 52 (b) 520 (c) 5200
  22. 22.√66 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.1 (d) 8.0
  23. 23.Best estimate of 6192 ÷ 69? (a) 8800 (b) 88 (c) 880
  24. 24.√92 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.6 (d) 9.3
  25. 25.Best estimate of 954 ÷ 23? (a) 48 (b) 480 (c) 4800
  26. 26.Best estimate of 1611 ÷ 53? (a) 3200 (b) 32 (c) 320
  27. 27.√45 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 6.9 (d) 7.0
  28. 28.Best estimate of 3612 ÷ 67? (a) 52 (b) 520 (c) 5200
  29. 29.√35 to 1 decimal place? (a) 5.8 (b) 5.6 (c) 5.9 (d) 5.7
  30. 30.Best estimate of 848 ÷ 38? (a) 2100 (b) 21 (c) 210
  31. 31.Best estimate of 4899 ÷ 56? (a) 8200 (b) 820 (c) 82
  32. 32.√80 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 9.0
  33. 33.√30 to 1 decimal place? (a) 5.6 (b) 5.4 (c) 5.5 (d) 5.3
  34. 34.Best estimate of 2063 ÷ 41? (a) 5200 (b) 52 (c) 520
  35. 35.√28 to 1 decimal place? (a) 5.4 (b) 5.6 (c) 5.5 (d) 5.3
  36. 36.√42 to 1 decimal place? (a) 6.8 (b) 6.5 (c) 6.6 (d) 6.7
  37. 37.Best estimate of 4851 ÷ 82? (a) 610 (b) 61 (c) 6100
  38. 38.Best estimate of 5769 ÷ 64? (a) 96 (b) 960 (c) 9600
  39. 39.Best estimate of 3613 ÷ 46? (a) 7200 (b) 72 (c) 720
  40. 40.√47 to 1 decimal place? (a) 6.7 (b) 7.0 (c) 6.8 (d) 6.9

Answer key

  1. 4.8
  2. 45
  3. 15
  4. 79
  5. 61
  6. 21
  7. 31
  8. 76
  9. 6.3
  10. 8.6
  11. 7.9
  12. 82
  13. 7.4
  14. 66
  15. 53
  16. 7.1
  17. 48
  18. 56
  19. 9.7
  20. 34
  21. 52
  22. 8.1
  23. 88
  24. 9.6
  25. 48
  26. 32
  27. 6.7
  28. 52
  29. 5.9
  30. 21
  31. 82
  32. 8.9
  33. 5.5
  34. 52
  35. 5.3
  36. 6.5
  37. 61
  38. 96
  39. 72
  40. 6.9

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