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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 302 · 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 1651 ÷ 66? (a) 24 (b) 2400 (c) 240
  2. 2.√44 to 1 decimal place? (a) 6.3 (b) 6.6 (c) 6.4 (d) 6.5
  3. 3.Best estimate of 1418 ÷ 32? (a) 47 (b) 4700 (c) 470
  4. 4.Best estimate of 536 ÷ 21? (a) 2700 (b) 270 (c) 27
  5. 5.√24 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 4.6 (d) 4.9
  6. 6.Best estimate of 2293 ÷ 67? (a) 330 (b) 33 (c) 3300
  7. 7.Best estimate of 1365 ÷ 79? (a) 17 (b) 170 (c) 1700
  8. 8.Best estimate of 6691 ÷ 73? (a) 9600 (b) 960 (c) 96
  9. 9.√90 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.5 (d) 9.3
  10. 10.√34 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 5.8 (d) 5.9
  11. 11.Best estimate of 1239 ÷ 34? (a) 4100 (b) 41 (c) 410
  12. 12.√37 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.3 (d) 6.1
  13. 13.√55 to 1 decimal place? (a) 7.1 (b) 7.4 (c) 7.2 (d) 7.3
  14. 14.Best estimate of 3243 ÷ 56? (a) 540 (b) 5400 (c) 54
  15. 15.Best estimate of 1146 ÷ 46? (a) 230 (b) 2300 (c) 23
  16. 16.Best estimate of 6806 ÷ 84? (a) 8500 (b) 850 (c) 85
  17. 17.√48 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.7 (d) 6.9
  18. 18.Best estimate of 1898 ÷ 81? (a) 24 (b) 2400 (c) 240
  19. 19.Best estimate of 1562 ÷ 82? (a) 2000 (b) 20 (c) 200
  20. 20.Best estimate of 1690 ÷ 67? (a) 24 (b) 2400 (c) 240
  21. 21.Best estimate of 4588 ÷ 57? (a) 7600 (b) 760 (c) 76
  22. 22.√84 to 1 decimal place? (a) 9.2 (b) 8.9 (c) 9.1 (d) 9.0
  23. 23.Best estimate of 1309 ÷ 63? (a) 22 (b) 220 (c) 2200
  24. 24.Best estimate of 3340 ÷ 89? (a) 3700 (b) 370 (c) 37
  25. 25.√23 to 1 decimal place? (a) 4.8 (b) 4.5 (c) 4.6 (d) 4.7
  26. 26.√38 to 1 decimal place? (a) 6.5 (b) 6.2 (c) 6.3 (d) 6.4
  27. 27.Best estimate of 5549 ÷ 61? (a) 92 (b) 9200 (c) 920
  28. 28.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.0 (d) 9.2
  29. 29.Best estimate of 914 ÷ 52? (a) 18 (b) 180 (c) 1800
  30. 30.Best estimate of 1025 ÷ 51? (a) 2100 (b) 210 (c) 21
  31. 31.Best estimate of 4757 ÷ 56? (a) 79 (b) 7900 (c) 790
  32. 32.√20 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.5 (d) 4.8
  33. 33.Best estimate of 4065 ÷ 71? (a) 580 (b) 5800 (c) 58
  34. 34.√77 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.7 (d) 8.8
  35. 35.Best estimate of 6533 ÷ 76? (a) 820 (b) 8200 (c) 82
  36. 36.√63 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.6 (d) 7.8
  37. 37.Best estimate of 1908 ÷ 78? (a) 2400 (b) 24 (c) 240
  38. 38.√98 to 1 decimal place? (a) 9.9 (b) 9.6 (c) 9.8 (d) 9.7
  39. 39.Best estimate of 962 ÷ 47? (a) 19 (b) 190 (c) 1900
  40. 40.Best estimate of 4358 ÷ 66? (a) 6200 (b) 62 (c) 620

Answer key

  1. 24
  2. 6.6
  3. 47
  4. 27
  5. 4.9
  6. 33
  7. 17
  8. 96
  9. 9.5
  10. 5.8
  11. 41
  12. 6.1
  13. 7.4
  14. 54
  15. 23
  16. 85
  17. 6.9
  18. 24
  19. 20
  20. 24
  21. 76
  22. 9.2
  23. 22
  24. 37
  25. 4.8
  26. 6.2
  27. 92
  28. 9.1
  29. 18
  30. 21
  31. 79
  32. 4.5
  33. 58
  34. 8.8
  35. 82
  36. 7.9
  37. 24
  38. 9.9
  39. 19
  40. 62

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