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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 546 · 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 3370 ÷ 41? (a) 8400 (b) 84 (c) 840
  2. 2.√80 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.9
  3. 3.Best estimate of 3656 ÷ 42? (a) 9100 (b) 91 (c) 910
  4. 4.Best estimate of 3610 ÷ 68? (a) 520 (b) 5200 (c) 52
  5. 5.√53 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.3 (d) 7.5
  6. 6.Best estimate of 2283 ÷ 24? (a) 1140 (b) 114 (c) 11400
  7. 7.Best estimate of 1654 ÷ 28? (a) 550 (b) 5500 (c) 55
  8. 8.Best estimate of 703 ÷ 26? (a) 230 (b) 23 (c) 2300
  9. 9.Best estimate of 1426 ÷ 58? (a) 24 (b) 240 (c) 2400
  10. 10.Best estimate of 3207 ÷ 63? (a) 53 (b) 530 (c) 5300
  11. 11.Best estimate of 8312 ÷ 88? (a) 9200 (b) 92 (c) 920
  12. 12.√76 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  13. 13.Best estimate of 1319 ÷ 36? (a) 330 (b) 33 (c) 3300
  14. 14.Best estimate of 5702 ÷ 84? (a) 7100 (b) 710 (c) 71
  15. 15.Best estimate of 2429 ÷ 86? (a) 270 (b) 27 (c) 2700
  16. 16.√67 to 1 decimal place? (a) 8.1 (b) 8.3 (c) 8.4 (d) 8.2
  17. 17.Best estimate of 1951 ÷ 66? (a) 2800 (b) 280 (c) 28
  18. 18.√82 to 1 decimal place? (a) 9.1 (b) 9.4 (c) 9.3 (d) 9.2
  19. 19.Best estimate of 2255 ÷ 51? (a) 450 (b) 45 (c) 4500
  20. 20.Best estimate of 2691 ÷ 66? (a) 380 (b) 38 (c) 3800
  21. 21.√24 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 5.1 (d) 4.8
  22. 22.Best estimate of 1898 ÷ 83? (a) 2400 (b) 24 (c) 240
  23. 23.Best estimate of 669 ÷ 21? (a) 330 (b) 3300 (c) 33
  24. 24.Best estimate of 3324 ÷ 69? (a) 4700 (b) 470 (c) 47
  25. 25.√79 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  26. 26.√62 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 7.6 (d) 7.7
  27. 27.Best estimate of 1708 ÷ 24? (a) 850 (b) 8500 (c) 85
  28. 28.Best estimate of 5391 ÷ 68? (a) 77 (b) 7700 (c) 770
  29. 29.Best estimate of 2686 ÷ 68? (a) 38 (b) 380 (c) 3800
  30. 30.Best estimate of 3442 ÷ 76? (a) 4300 (b) 43 (c) 430
  31. 31.√29 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.5 (d) 5.4
  32. 32.√88 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.3 (d) 9.6
  33. 33.√89 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.3 (d) 9.5
  34. 34.Best estimate of 6287 ÷ 83? (a) 790 (b) 79 (c) 7900
  35. 35.√70 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.4 (d) 8.5
  36. 36.Best estimate of 807 ÷ 32? (a) 2700 (b) 27 (c) 270
  37. 37.Best estimate of 4631 ÷ 56? (a) 770 (b) 7700 (c) 77
  38. 38.Best estimate of 6057 ÷ 88? (a) 6700 (b) 67 (c) 670
  39. 39.Best estimate of 4624 ÷ 52? (a) 9200 (b) 92 (c) 920
  40. 40.√30 to 1 decimal place? (a) 5.3 (b) 5.5 (c) 5.4 (d) 5.2

Answer key

  1. 84
  2. 8.9
  3. 91
  4. 52
  5. 7.3
  6. 114
  7. 55
  8. 23
  9. 24
  10. 53
  11. 92
  12. 8.7
  13. 33
  14. 71
  15. 27
  16. 8.2
  17. 28
  18. 9.1
  19. 45
  20. 38
  21. 4.9
  22. 24
  23. 33
  24. 47
  25. 8.9
  26. 7.9
  27. 85
  28. 77
  29. 38
  30. 43
  31. 5.4
  32. 9.4
  33. 9.4
  34. 79
  35. 8.4
  36. 27
  37. 77
  38. 67
  39. 92
  40. 5.5

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