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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 599 · 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.√76 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.4 (d) 8.6
  2. 2.√77 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  3. 3.Best estimate of 1240 ÷ 21? (a) 6200 (b) 62 (c) 620
  4. 4.√26 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.0 (d) 5.2
  5. 5.Best estimate of 2198 ÷ 76? (a) 27 (b) 2700 (c) 270
  6. 6.√83 to 1 decimal place? (a) 9.3 (b) 9.0 (c) 9.2 (d) 9.1
  7. 7.√20 to 1 decimal place? (a) 4.5 (b) 4.8 (c) 4.7 (d) 4.6
  8. 8.Best estimate of 3584 ÷ 47? (a) 7200 (b) 720 (c) 72
  9. 9.√21 to 1 decimal place? (a) 4.6 (b) 4.9 (c) 4.8 (d) 4.7
  10. 10.√51 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 6.9 (d) 7.0
  11. 11.√82 to 1 decimal place? (a) 9.2 (b) 8.9 (c) 9.1 (d) 9.0
  12. 12.√90 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.3 (d) 9.2
  13. 13.Best estimate of 2977 ÷ 39? (a) 740 (b) 7400 (c) 74
  14. 14.√59 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.8 (d) 7.6
  15. 15.Best estimate of 4503 ÷ 84? (a) 5600 (b) 56 (c) 560
  16. 16.√42 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.5 (d) 6.4
  17. 17.Best estimate of 1218 ÷ 44? (a) 3000 (b) 300 (c) 30
  18. 18.Best estimate of 3228 ÷ 37? (a) 8100 (b) 810 (c) 81
  19. 19.Best estimate of 586 ÷ 24? (a) 290 (b) 29 (c) 2900
  20. 20.Best estimate of 1556 ÷ 26? (a) 520 (b) 5200 (c) 52
  21. 21.Best estimate of 1475 ÷ 71? (a) 21 (b) 2100 (c) 210
  22. 22.√45 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 6.6
  23. 23.√75 to 1 decimal place? (a) 8.8 (b) 8.6 (c) 8.5 (d) 8.7
  24. 24.√34 to 1 decimal place? (a) 5.7 (b) 5.5 (c) 5.6 (d) 5.8
  25. 25.Best estimate of 1110 ÷ 83? (a) 1400 (b) 14 (c) 140
  26. 26.Best estimate of 1501 ÷ 78? (a) 190 (b) 19 (c) 1900
  27. 27.√29 to 1 decimal place? (a) 5.4 (b) 5.6 (c) 5.3 (d) 5.5
  28. 28.Best estimate of 2153 ÷ 28? (a) 7200 (b) 720 (c) 72
  29. 29.√37 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.3 (d) 6.1
  30. 30.√69 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.0 (d) 8.1
  31. 31.√38 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 5.9 (d) 6.0
  32. 32.Best estimate of 4044 ÷ 54? (a) 810 (b) 81 (c) 8100
  33. 33.√43 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.5 (d) 6.7
  34. 34.Best estimate of 1258 ÷ 32? (a) 42 (b) 420 (c) 4200
  35. 35.Best estimate of 1988 ÷ 86? (a) 220 (b) 2200 (c) 22
  36. 36.Best estimate of 2113 ÷ 24? (a) 10600 (b) 106 (c) 1060
  37. 37.Best estimate of 3309 ÷ 37? (a) 830 (b) 83 (c) 8300
  38. 38.Best estimate of 1750 ÷ 66? (a) 2500 (b) 25 (c) 250
  39. 39.Best estimate of 1148 ÷ 22? (a) 570 (b) 5700 (c) 57
  40. 40.√48 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 7.1 (d) 6.8

Answer key

  1. 8.7
  2. 8.8
  3. 62
  4. 5.1
  5. 27
  6. 9.1
  7. 4.5
  8. 72
  9. 4.6
  10. 7.1
  11. 9.1
  12. 9.5
  13. 74
  14. 7.7
  15. 56
  16. 6.5
  17. 30
  18. 81
  19. 29
  20. 52
  21. 21
  22. 6.7
  23. 8.7
  24. 5.8
  25. 14
  26. 19
  27. 5.4
  28. 72
  29. 6.1
  30. 8.3
  31. 6.2
  32. 81
  33. 6.6
  34. 42
  35. 22
  36. 106
  37. 83
  38. 25
  39. 57
  40. 6.9

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