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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 538 · 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 660 ÷ 24? (a) 3300 (b) 330 (c) 33
  2. 2.Best estimate of 3761 ÷ 58? (a) 6300 (b) 630 (c) 63
  3. 3.Best estimate of 2349 ÷ 43? (a) 590 (b) 5900 (c) 59
  4. 4.Best estimate of 1040 ÷ 26? (a) 35 (b) 350 (c) 3500
  5. 5.Best estimate of 2889 ÷ 49? (a) 580 (b) 5800 (c) 58
  6. 6.Best estimate of 8255 ÷ 86? (a) 92 (b) 920 (c) 9200
  7. 7.Best estimate of 6745 ÷ 77? (a) 840 (b) 84 (c) 8400
  8. 8.√52 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.0 (d) 7.3
  9. 9.√42 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.2 (d) 6.5
  10. 10.Best estimate of 6506 ÷ 72? (a) 9300 (b) 930 (c) 93
  11. 11.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 9.0 (d) 8.9
  12. 12.√78 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.8 (d) 8.7
  13. 13.√77 to 1 decimal place? (a) 9.0 (b) 8.7 (c) 8.9 (d) 8.8
  14. 14.√79 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.1 (d) 9.2
  15. 15.Best estimate of 1255 ÷ 31? (a) 420 (b) 42 (c) 4200
  16. 16.√88 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.5 (d) 9.6
  17. 17.Best estimate of 6272 ÷ 76? (a) 7800 (b) 780 (c) 78
  18. 18.√44 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.8 (d) 6.5
  19. 19.√28 to 1 decimal place? (a) 5.3 (b) 5.5 (c) 5.6 (d) 5.4
  20. 20.√69 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.3 (d) 8.2
  21. 21.Best estimate of 2305 ÷ 82? (a) 2900 (b) 29 (c) 290
  22. 22.Best estimate of 2074 ÷ 39? (a) 52 (b) 5200 (c) 520
  23. 23.√38 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 6.3 (d) 6.2
  24. 24.Best estimate of 3893 ÷ 54? (a) 780 (b) 7800 (c) 78
  25. 25.Best estimate of 1124 ÷ 56? (a) 19 (b) 190 (c) 1900
  26. 26.√24 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.2 (d) 4.9
  27. 27.√41 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.1 (d) 6.3
  28. 28.Best estimate of 3434 ÷ 66? (a) 4900 (b) 490 (c) 49
  29. 29.√32 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.4 (d) 5.5
  30. 30.Best estimate of 1662 ÷ 32? (a) 5500 (b) 550 (c) 55
  31. 31.Best estimate of 1830 ÷ 22? (a) 920 (b) 9200 (c) 92
  32. 32.Best estimate of 625 ÷ 36? (a) 16 (b) 1600 (c) 160
  33. 33.√56 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.3 (d) 7.2
  34. 34.Best estimate of 2660 ÷ 28? (a) 8900 (b) 890 (c) 89
  35. 35.Best estimate of 654 ÷ 36? (a) 1600 (b) 160 (c) 16
  36. 36.√89 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.4 (d) 9.3
  37. 37.Best estimate of 2156 ÷ 76? (a) 27 (b) 270 (c) 2700
  38. 38.√26 to 1 decimal place? (a) 5.3 (b) 5.0 (c) 5.2 (d) 5.1
  39. 39.√43 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 6.6 (d) 6.7
  40. 40.Best estimate of 1072 ÷ 41? (a) 270 (b) 2700 (c) 27

Answer key

  1. 33
  2. 63
  3. 59
  4. 35
  5. 58
  6. 92
  7. 84
  8. 7.2
  9. 6.5
  10. 93
  11. 8.7
  12. 8.8
  13. 8.8
  14. 8.9
  15. 42
  16. 9.4
  17. 78
  18. 6.6
  19. 5.3
  20. 8.3
  21. 29
  22. 52
  23. 6.2
  24. 78
  25. 19
  26. 4.9
  27. 6.4
  28. 49
  29. 5.7
  30. 55
  31. 92
  32. 16
  33. 7.5
  34. 89
  35. 16
  36. 9.4
  37. 27
  38. 5.1
  39. 6.6
  40. 27

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