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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 564 · 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 3527 ÷ 58? (a) 5900 (b) 590 (c) 59
  2. 2.Best estimate of 2504 ÷ 36? (a) 63 (b) 6300 (c) 630
  3. 3.Best estimate of 3121 ÷ 37? (a) 780 (b) 78 (c) 7800
  4. 4.Best estimate of 4557 ÷ 51? (a) 9100 (b) 910 (c) 91
  5. 5.√24 to 1 decimal place? (a) 4.9 (b) 4.6 (c) 4.7 (d) 4.8
  6. 6.Best estimate of 4224 ÷ 58? (a) 700 (b) 70 (c) 7000
  7. 7.Best estimate of 1787 ÷ 52? (a) 36 (b) 3600 (c) 360
  8. 8.Best estimate of 4428 ÷ 81? (a) 550 (b) 5500 (c) 55
  9. 9.Best estimate of 1284 ÷ 52? (a) 260 (b) 2600 (c) 26
  10. 10.Best estimate of 1458 ÷ 71? (a) 2100 (b) 210 (c) 21
  11. 11.Best estimate of 3978 ÷ 52? (a) 8000 (b) 800 (c) 80
  12. 12.Best estimate of 647 ÷ 32? (a) 2200 (b) 22 (c) 220
  13. 13.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.4
  14. 14.Best estimate of 1283 ÷ 66? (a) 1800 (b) 18 (c) 180
  15. 15.Best estimate of 3071 ÷ 52? (a) 610 (b) 6100 (c) 61
  16. 16.√67 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.0 (d) 8.1
  17. 17.Best estimate of 5227 ÷ 86? (a) 580 (b) 5800 (c) 58
  18. 18.√84 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.4 (d) 9.2
  19. 19.Best estimate of 4601 ÷ 67? (a) 660 (b) 6600 (c) 66
  20. 20.√29 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.3 (d) 5.6
  21. 21.√72 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.3 (d) 8.4
  22. 22.Best estimate of 1446 ÷ 73? (a) 210 (b) 2100 (c) 21
  23. 23.Best estimate of 1369 ÷ 21? (a) 68 (b) 680 (c) 6800
  24. 24.Best estimate of 1479 ÷ 36? (a) 370 (b) 37 (c) 3700
  25. 25.Best estimate of 2789 ÷ 41? (a) 700 (b) 7000 (c) 70
  26. 26.√41 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.4 (d) 6.2
  27. 27.√94 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.8 (d) 9.7
  28. 28.Best estimate of 6751 ÷ 82? (a) 84 (b) 8400 (c) 840
  29. 29.Best estimate of 3251 ÷ 59? (a) 54 (b) 5400 (c) 540
  30. 30.√34 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.6 (d) 5.8
  31. 31.√92 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.5 (d) 9.3
  32. 32.√27 to 1 decimal place? (a) 5.3 (b) 5.5 (c) 5.4 (d) 5.2
  33. 33.Best estimate of 2600 ÷ 28? (a) 870 (b) 87 (c) 8700
  34. 34.√53 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.3 (d) 7.5
  35. 35.√98 to 1 decimal place? (a) 10.2 (b) 10.0 (c) 10.1 (d) 9.9
  36. 36.Best estimate of 865 ÷ 54? (a) 1700 (b) 170 (c) 17
  37. 37.Best estimate of 1773 ÷ 62? (a) 300 (b) 3000 (c) 30
  38. 38.Best estimate of 3031 ÷ 69? (a) 430 (b) 43 (c) 4300
  39. 39.Best estimate of 4262 ÷ 56? (a) 71 (b) 710 (c) 7100
  40. 40.√79 to 1 decimal place? (a) 8.9 (b) 8.6 (c) 8.7 (d) 8.8

Answer key

  1. 59
  2. 63
  3. 78
  4. 91
  5. 4.9
  6. 70
  7. 36
  8. 55
  9. 26
  10. 21
  11. 80
  12. 22
  13. 8.1
  14. 18
  15. 61
  16. 8.2
  17. 58
  18. 9.2
  19. 66
  20. 5.4
  21. 8.5
  22. 21
  23. 68
  24. 37
  25. 70
  26. 6.4
  27. 9.7
  28. 84
  29. 54
  30. 5.8
  31. 9.6
  32. 5.2
  33. 87
  34. 7.3
  35. 9.9
  36. 17
  37. 30
  38. 43
  39. 71
  40. 8.9

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