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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 568 · 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.√53 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.4 (d) 7.3
  2. 2.√50 to 1 decimal place? (a) 7.0 (b) 7.2 (c) 7.1 (d) 7.3
  3. 3.√69 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.4 (d) 8.5
  4. 4.√92 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.5 (d) 9.4
  5. 5.√74 to 1 decimal place? (a) 8.7 (b) 8.4 (c) 8.5 (d) 8.6
  6. 6.√59 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.7 (d) 7.9
  7. 7.Best estimate of 5684 ÷ 69? (a) 810 (b) 8100 (c) 81
  8. 8.√34 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.7 (d) 5.9
  9. 9.Best estimate of 6362 ÷ 67? (a) 9100 (b) 91 (c) 910
  10. 10.Best estimate of 503 ÷ 26? (a) 17 (b) 170 (c) 1700
  11. 11.√43 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.5 (d) 6.4
  12. 12.√78 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.5 (d) 8.8
  13. 13.Best estimate of 2122 ÷ 62? (a) 35 (b) 3500 (c) 350
  14. 14.Best estimate of 2328 ÷ 72? (a) 330 (b) 3300 (c) 33
  15. 15.√41 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.5 (d) 6.6
  16. 16.Best estimate of 1231 ÷ 32? (a) 4100 (b) 410 (c) 41
  17. 17.Best estimate of 3242 ÷ 64? (a) 54 (b) 540 (c) 5400
  18. 18.√71 to 1 decimal place? (a) 8.6 (b) 8.3 (c) 8.5 (d) 8.4
  19. 19.√76 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  20. 20.√32 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 6.0 (d) 5.7
  21. 21.Best estimate of 2706 ÷ 82? (a) 3400 (b) 34 (c) 340
  22. 22.√46 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.5 (d) 6.6
  23. 23.√86 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.0 (d) 9.1
  24. 24.Best estimate of 389 ÷ 21? (a) 190 (b) 1900 (c) 19
  25. 25.Best estimate of 4614 ÷ 52? (a) 920 (b) 9200 (c) 92
  26. 26.Best estimate of 1092 ÷ 46? (a) 2200 (b) 220 (c) 22
  27. 27.√28 to 1 decimal place? (a) 5.6 (b) 5.3 (c) 5.4 (d) 5.5
  28. 28.√96 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.5 (d) 9.8
  29. 29.Best estimate of 1821 ÷ 68? (a) 2600 (b) 260 (c) 26
  30. 30.√42 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.5 (d) 6.7
  31. 31.Best estimate of 2082 ÷ 28? (a) 6900 (b) 690 (c) 69
  32. 32.Best estimate of 2126 ÷ 68? (a) 300 (b) 3000 (c) 30
  33. 33.Best estimate of 720 ÷ 24? (a) 360 (b) 3600 (c) 36
  34. 34.√83 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.1 (d) 9.4
  35. 35.Best estimate of 4514 ÷ 76? (a) 56 (b) 560 (c) 5600
  36. 36.Best estimate of 2265 ÷ 42? (a) 570 (b) 5700 (c) 57
  37. 37.Best estimate of 1064 ÷ 39? (a) 27 (b) 270 (c) 2700
  38. 38.√87 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 9.3
  39. 39.Best estimate of 3927 ÷ 58? (a) 65 (b) 6500 (c) 650
  40. 40.Best estimate of 3426 ÷ 37? (a) 860 (b) 8600 (c) 86

Answer key

  1. 7.3
  2. 7.1
  3. 8.3
  4. 9.6
  5. 8.6
  6. 7.7
  7. 81
  8. 5.8
  9. 91
  10. 17
  11. 6.6
  12. 8.8
  13. 35
  14. 33
  15. 6.4
  16. 41
  17. 54
  18. 8.4
  19. 8.7
  20. 5.7
  21. 34
  22. 6.8
  23. 9.3
  24. 19
  25. 92
  26. 22
  27. 5.3
  28. 9.8
  29. 26
  30. 6.5
  31. 69
  32. 30
  33. 36
  34. 9.1
  35. 56
  36. 57
  37. 27
  38. 9.3
  39. 65
  40. 86

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