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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 486 · 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.Best estimate of 772 ÷ 59? (a) 13 (b) 1300 (c) 130
  2. 2.Best estimate of 6524 ÷ 84? (a) 820 (b) 8200 (c) 82
  3. 3.Best estimate of 2713 ÷ 29? (a) 9000 (b) 90 (c) 900
  4. 4.Best estimate of 2505 ÷ 39? (a) 630 (b) 6300 (c) 63
  5. 5.√51 to 1 decimal place? (a) 7.2 (b) 7.4 (c) 7.3 (d) 7.1
  6. 6.Best estimate of 2207 ÷ 29? (a) 74 (b) 7400 (c) 740
  7. 7.Best estimate of 1153 ÷ 53? (a) 2300 (b) 230 (c) 23
  8. 8.√78 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.7 (d) 8.8
  9. 9.√40 to 1 decimal place? (a) 6.2 (b) 6.1 (c) 6.3 (d) 6.4
  10. 10.Best estimate of 2593 ÷ 34? (a) 860 (b) 86 (c) 8600
  11. 11.Best estimate of 1175 ÷ 77? (a) 15 (b) 1500 (c) 150
  12. 12.√65 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 8.1 (d) 7.9
  13. 13.√79 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.9 (d) 8.8
  14. 14.√42 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.5 (d) 6.4
  15. 15.Best estimate of 1637 ÷ 24? (a) 82 (b) 820 (c) 8200
  16. 16.Best estimate of 2254 ÷ 86? (a) 250 (b) 2500 (c) 25
  17. 17.√84 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.1 (d) 9.0
  18. 18.√96 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.8 (d) 9.7
  19. 19.Best estimate of 1590 ÷ 87? (a) 18 (b) 1800 (c) 180
  20. 20.Best estimate of 1081 ÷ 77? (a) 14 (b) 140 (c) 1400
  21. 21.√83 to 1 decimal place? (a) 8.8 (b) 9.1 (c) 8.9 (d) 9.0
  22. 22.Best estimate of 498 ÷ 37? (a) 1200 (b) 120 (c) 12
  23. 23.Best estimate of 923 ÷ 76? (a) 120 (b) 1200 (c) 12
  24. 24.Best estimate of 5266 ÷ 72? (a) 7500 (b) 750 (c) 75
  25. 25.√89 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.3 (d) 9.6
  26. 26.√35 to 1 decimal place? (a) 5.9 (b) 5.6 (c) 5.7 (d) 5.8
  27. 27.√32 to 1 decimal place? (a) 5.7 (b) 6.0 (c) 5.9 (d) 5.8
  28. 28.√34 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.6 (d) 5.8
  29. 29.Best estimate of 2455 ÷ 42? (a) 61 (b) 6100 (c) 610
  30. 30.√20 to 1 decimal place? (a) 4.5 (b) 4.4 (c) 4.7 (d) 4.6
  31. 31.Best estimate of 6974 ÷ 74? (a) 1000 (b) 100 (c) 10000
  32. 32.Best estimate of 2696 ÷ 39? (a) 67 (b) 6700 (c) 670
  33. 33.√48 to 1 decimal place? (a) 7.0 (b) 6.8 (c) 6.7 (d) 6.9
  34. 34.√37 to 1 decimal place? (a) 6.1 (b) 5.9 (c) 6.0 (d) 5.8
  35. 35.√82 to 1 decimal place? (a) 9.2 (b) 9.0 (c) 8.9 (d) 9.1
  36. 36.Best estimate of 428 ÷ 27? (a) 140 (b) 14 (c) 1400
  37. 37.Best estimate of 4800 ÷ 76? (a) 6000 (b) 600 (c) 60
  38. 38.Best estimate of 3890 ÷ 51? (a) 78 (b) 780 (c) 7800
  39. 39.Best estimate of 1688 ÷ 32? (a) 5600 (b) 560 (c) 56
  40. 40.Best estimate of 1620 ÷ 49? (a) 3200 (b) 320 (c) 32

Answer key

  1. 13
  2. 82
  3. 90
  4. 63
  5. 7.1
  6. 74
  7. 23
  8. 8.8
  9. 6.3
  10. 86
  11. 15
  12. 8.1
  13. 8.9
  14. 6.5
  15. 82
  16. 25
  17. 9.2
  18. 9.8
  19. 18
  20. 14
  21. 9.1
  22. 12
  23. 12
  24. 75
  25. 9.4
  26. 5.9
  27. 5.7
  28. 5.8
  29. 61
  30. 4.5
  31. 100
  32. 67
  33. 6.9
  34. 6.1
  35. 9.1
  36. 14
  37. 60
  38. 78
  39. 56
  40. 32

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