Answer:
 1/4, 2/5, 1/2, 3/5, 2/3, 13/18, 7/9, 5/6, 2 6/15, 2 4/9, 2 3/5, 2 2/3, 6 3/8, 6 1/2, 
6 3/4, 6 5/6
Explanation:
I like to organize decimals more than fractions because it's easier for me, so I'm changing each of them to a decimal. You don't have to do this though.
- To change a fraction to a decimal, if it is simplified, make it an improper fraction
 - Then, divide the numerator from the denominator. For example, 1/4 = 0.25 because 1 divided by 4 = 0.25
 
- 3/5 = 0.60, 
 - 1/4 = 0.25, 
 - 1/2 = 0.50, 
 - 2/5 = 0.40, 
 - 7/9 = 0.7 repeating or just 0.78 rounded, 
 - 13/18 = 0.72 repeating or 0.73 rounded, 
 - 5/6 = 0.83 repeating or 0.84 rounded, 
 - 2/3 = 0.66 repeating or 0.67 simplified, 
 - 6 3/4 = 27/4 or 6.75,
 - 6 1/2 = 13/2 = 6.50,
 - 6 5/6 = 41/6 = 6.83 repeating or 6.84
 - 6 3/8 = 51/8 = 6.375 or 6.38
 - 2 2/3 = 8/3 = 2.66 repeating or 2.67
 - 2 6/15 = 36/15 = 2.40
 - 2 3/5 = 13/5 = 2.60
 - 2 4/9 = 22/9 = 2.44 repeating or 2.45
 
Ordering them is pretty easy, just start from the smallest and move to the greatest!
- 0.25 = 1/4
 - 0.40 = 2/5
 - 0.50 = 1/2
 - 0.60 = 3/5
 - 0.67 = 2/3
 - 0.73 = 13/18
 - 0.78 = 7/9
 - 0.84 = 5/6
 - 2.40 = 2 6/15
 - 2.45 = 2 4/9
 - 2.60 = 2 3/5
 - 2.67 = 2 2/3
 - 6.38 = 6 3/8
 - 6.50 = 6 1/2 
 - 6.75 = 6 3/4
 - 6.84 = 6 5/6