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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 615 · 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.√55 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.4 (d) 7.3
  2. 2.Best estimate of 1794 ÷ 49? (a) 36 (b) 3600 (c) 360
  3. 3.Best estimate of 532 ÷ 21? (a) 270 (b) 2700 (c) 27
  4. 4.Best estimate of 4949 ÷ 72? (a) 71 (b) 710 (c) 7100
  5. 5.Best estimate of 3223 ÷ 69? (a) 46 (b) 460 (c) 4600
  6. 6.Best estimate of 3050 ÷ 56? (a) 510 (b) 5100 (c) 51
  7. 7.√96 to 1 decimal place? (a) 10.1 (b) 9.9 (c) 10.0 (d) 9.8
  8. 8.√70 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.7 (d) 8.4
  9. 9.√34 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 6.0 (d) 5.9
  10. 10.√37 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 6.3
  11. 11.√61 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.9 (d) 7.6
  12. 12.Best estimate of 4117 ÷ 79? (a) 51 (b) 510 (c) 5100
  13. 13.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.6 (d) 9.7
  14. 14.√87 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.5 (d) 9.3
  15. 15.√67 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.5 (d) 8.2
  16. 16.√26 to 1 decimal place? (a) 5.0 (b) 5.3 (c) 5.1 (d) 5.2
  17. 17.√29 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.6 (d) 5.5
  18. 18.Best estimate of 3717 ÷ 72? (a) 530 (b) 5300 (c) 53
  19. 19.Best estimate of 6409 ÷ 71? (a) 920 (b) 9200 (c) 92
  20. 20.Best estimate of 2905 ÷ 39? (a) 7300 (b) 73 (c) 730
  21. 21.√59 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.9 (d) 7.7
  22. 22.Best estimate of 2137 ÷ 43? (a) 5300 (b) 530 (c) 53
  23. 23.√77 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 8.7 (d) 8.6
  24. 24.Best estimate of 7417 ÷ 86? (a) 8200 (b) 820 (c) 82
  25. 25.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.4 (d) 8.3
  26. 26.Best estimate of 1205 ÷ 89? (a) 130 (b) 1300 (c) 13
  27. 27.√45 to 1 decimal place? (a) 6.4 (b) 6.7 (c) 6.6 (d) 6.5
  28. 28.Best estimate of 2347 ÷ 53? (a) 470 (b) 4700 (c) 47
  29. 29.√28 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.0 (d) 5.2
  30. 30.Best estimate of 5069 ÷ 56? (a) 84 (b) 840 (c) 8400
  31. 31.Best estimate of 3766 ÷ 53? (a) 750 (b) 75 (c) 7500
  32. 32.Best estimate of 6289 ÷ 69? (a) 90 (b) 900 (c) 9000
  33. 33.Best estimate of 4414 ÷ 51? (a) 8800 (b) 880 (c) 88
  34. 34.Best estimate of 4889 ÷ 58? (a) 8100 (b) 810 (c) 81
  35. 35.Best estimate of 1034 ÷ 48? (a) 2100 (b) 210 (c) 21
  36. 36.Best estimate of 1493 ÷ 31? (a) 50 (b) 5000 (c) 500
  37. 37.Best estimate of 2287 ÷ 26? (a) 76 (b) 7600 (c) 760
  38. 38.Best estimate of 7337 ÷ 86? (a) 820 (b) 82 (c) 8200
  39. 39.Best estimate of 3897 ÷ 63? (a) 6500 (b) 65 (c) 650
  40. 40.Best estimate of 5103 ÷ 68? (a) 7300 (b) 730 (c) 73

Answer key

  1. 7.4
  2. 36
  3. 27
  4. 71
  5. 46
  6. 51
  7. 9.8
  8. 8.4
  9. 5.8
  10. 6.1
  11. 7.8
  12. 51
  13. 9.9
  14. 9.3
  15. 8.2
  16. 5.1
  17. 5.4
  18. 53
  19. 92
  20. 73
  21. 7.7
  22. 53
  23. 8.8
  24. 82
  25. 8.1
  26. 13
  27. 6.7
  28. 47
  29. 5.3
  30. 84
  31. 75
  32. 90
  33. 88
  34. 81
  35. 21
  36. 50
  37. 76
  38. 82
  39. 65
  40. 73

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