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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 576 · 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) 8.2 (b) 8.0 (c) 8.1 (d) 8.3
  2. 2.Best estimate of 2341 ÷ 44? (a) 590 (b) 5900 (c) 59
  3. 3.√88 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.4 (d) 9.5
  4. 4.Best estimate of 3466 ÷ 41? (a) 8700 (b) 870 (c) 87
  5. 5.Best estimate of 2112 ÷ 26? (a) 700 (b) 7000 (c) 70
  6. 6.√58 to 1 decimal place? (a) 7.7 (b) 7.4 (c) 7.6 (d) 7.5
  7. 7.√37 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 5.9 (d) 5.8
  8. 8.Best estimate of 2195 ÷ 43? (a) 55 (b) 550 (c) 5500
  9. 9.Best estimate of 1721 ÷ 29? (a) 57 (b) 570 (c) 5700
  10. 10.Best estimate of 3547 ÷ 57? (a) 5900 (b) 590 (c) 59
  11. 11.√74 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.5 (d) 8.7
  12. 12.√48 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 6.9 (d) 7.0
  13. 13.√42 to 1 decimal place? (a) 6.5 (b) 6.7 (c) 6.4 (d) 6.6
  14. 14.√31 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.5 (d) 5.6
  15. 15.Best estimate of 4069 ÷ 43? (a) 1020 (b) 10200 (c) 102
  16. 16.Best estimate of 1795 ÷ 41? (a) 4500 (b) 450 (c) 45
  17. 17.Best estimate of 1186 ÷ 42? (a) 3000 (b) 300 (c) 30
  18. 18.Best estimate of 6601 ÷ 87? (a) 73 (b) 7300 (c) 730
  19. 19.√94 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.5
  20. 20.√98 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.8 (d) 9.6
  21. 21.Best estimate of 6876 ÷ 76? (a) 860 (b) 86 (c) 8600
  22. 22.Best estimate of 1888 ÷ 42? (a) 4700 (b) 470 (c) 47
  23. 23.Best estimate of 1692 ÷ 28? (a) 5600 (b) 560 (c) 56
  24. 24.Best estimate of 3455 ÷ 52? (a) 6900 (b) 69 (c) 690
  25. 25.Best estimate of 2808 ÷ 32? (a) 94 (b) 9400 (c) 940
  26. 26.√84 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.0 (d) 8.9
  27. 27.√70 to 1 decimal place? (a) 8.2 (b) 8.5 (c) 8.3 (d) 8.4
  28. 28.Best estimate of 3303 ÷ 47? (a) 66 (b) 6600 (c) 660
  29. 29.√59 to 1 decimal place? (a) 7.6 (b) 7.9 (c) 7.8 (d) 7.7
  30. 30.Best estimate of 1152 ÷ 37? (a) 2900 (b) 29 (c) 290
  31. 31.√65 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 7.8
  32. 32.√20 to 1 decimal place? (a) 4.4 (b) 4.3 (c) 4.5 (d) 4.2
  33. 33.√34 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 5.7 (d) 5.9
  34. 34.√63 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.9 (d) 7.6
  35. 35.Best estimate of 669 ÷ 33? (a) 22 (b) 220 (c) 2200
  36. 36.√77 to 1 decimal place? (a) 8.5 (b) 8.7 (c) 8.8 (d) 8.6
  37. 37.Best estimate of 627 ÷ 42? (a) 1600 (b) 16 (c) 160
  38. 38.Best estimate of 2572 ÷ 39? (a) 6400 (b) 64 (c) 640
  39. 39.Best estimate of 1081 ÷ 42? (a) 270 (b) 2700 (c) 27
  40. 40.Best estimate of 7447 ÷ 83? (a) 93 (b) 9300 (c) 930

Answer key

  1. 8.2
  2. 59
  3. 9.4
  4. 87
  5. 70
  6. 7.6
  7. 6.1
  8. 55
  9. 57
  10. 59
  11. 8.6
  12. 6.9
  13. 6.5
  14. 5.6
  15. 102
  16. 45
  17. 30
  18. 73
  19. 9.7
  20. 9.9
  21. 86
  22. 47
  23. 56
  24. 69
  25. 94
  26. 9.2
  27. 8.4
  28. 66
  29. 7.7
  30. 29
  31. 8.1
  32. 4.5
  33. 5.8
  34. 7.9
  35. 22
  36. 8.8
  37. 16
  38. 64
  39. 27
  40. 93

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