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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 490 · 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.√55 to 1 decimal place? (a) 7.7 (b) 7.4 (c) 7.6 (d) 7.5
  2. 2.Best estimate of 3937 ÷ 44? (a) 98 (b) 980 (c) 9800
  3. 3.Best estimate of 5163 ÷ 82? (a) 6500 (b) 65 (c) 650
  4. 4.Best estimate of 2405 ÷ 32? (a) 800 (b) 8000 (c) 80
  5. 5.√83 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.4 (d) 9.1
  6. 6.Best estimate of 2611 ÷ 57? (a) 44 (b) 440 (c) 4400
  7. 7.√59 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.8 (d) 7.7
  8. 8.√40 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.4
  9. 9.Best estimate of 5458 ÷ 63? (a) 9100 (b) 910 (c) 91
  10. 10.Best estimate of 631 ÷ 37? (a) 1600 (b) 160 (c) 16
  11. 11.√88 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.4 (d) 9.7
  12. 12.Best estimate of 389 ÷ 27? (a) 130 (b) 13 (c) 1300
  13. 13.Best estimate of 7653 ÷ 81? (a) 960 (b) 9600 (c) 96
  14. 14.√94 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.7 (d) 9.4
  15. 15.√43 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.5 (d) 6.4
  16. 16.√45 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 6.9 (d) 7.0
  17. 17.Best estimate of 1721 ÷ 53? (a) 340 (b) 3400 (c) 34
  18. 18.Best estimate of 1458 ÷ 43? (a) 360 (b) 36 (c) 3600
  19. 19.Best estimate of 4474 ÷ 67? (a) 640 (b) 64 (c) 6400
  20. 20.Best estimate of 3532 ÷ 39? (a) 88 (b) 8800 (c) 880
  21. 21.Best estimate of 2777 ÷ 32? (a) 9300 (b) 930 (c) 93
  22. 22.Best estimate of 1179 ÷ 39? (a) 29 (b) 290 (c) 2900
  23. 23.Best estimate of 3927 ÷ 64? (a) 6500 (b) 65 (c) 650
  24. 24.√47 to 1 decimal place? (a) 7.1 (b) 7.0 (c) 7.2 (d) 6.9
  25. 25.Best estimate of 2238 ÷ 66? (a) 32 (b) 3200 (c) 320
  26. 26.Best estimate of 2175 ÷ 32? (a) 7300 (b) 73 (c) 730
  27. 27.Best estimate of 5478 ÷ 71? (a) 7800 (b) 780 (c) 78
  28. 28.√98 to 1 decimal place? (a) 9.8 (b) 10.0 (c) 9.7 (d) 9.9
  29. 29.√37 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.0 (d) 6.2
  30. 30.Best estimate of 6829 ÷ 78? (a) 8500 (b) 850 (c) 85
  31. 31.Best estimate of 1933 ÷ 73? (a) 280 (b) 28 (c) 2800
  32. 32.Best estimate of 1783 ÷ 34? (a) 59 (b) 590 (c) 5900
  33. 33.Best estimate of 5531 ÷ 62? (a) 920 (b) 92 (c) 9200
  34. 34.√24 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.2 (d) 4.9
  35. 35.Best estimate of 1455 ÷ 39? (a) 3600 (b) 360 (c) 36
  36. 36.√67 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.2
  37. 37.Best estimate of 2187 ÷ 24? (a) 10900 (b) 109 (c) 1090
  38. 38.√48 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 7.2 (d) 6.9
  39. 39.√41 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.4 (d) 6.1
  40. 40.√28 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.2 (d) 5.0

Answer key

  1. 7.4
  2. 98
  3. 65
  4. 80
  5. 9.1
  6. 44
  7. 7.7
  8. 6.3
  9. 91
  10. 16
  11. 9.4
  12. 13
  13. 96
  14. 9.7
  15. 6.6
  16. 6.7
  17. 34
  18. 36
  19. 64
  20. 88
  21. 93
  22. 29
  23. 65
  24. 6.9
  25. 32
  26. 73
  27. 78
  28. 9.9
  29. 6.1
  30. 85
  31. 28
  32. 59
  33. 92
  34. 4.9
  35. 36
  36. 8.2
  37. 109
  38. 6.9
  39. 6.4
  40. 5.3

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