Before we convert these fractions from least to greatest, first convert them to decimal form to make the process easier.
1/2 becomes 0.5
2/3 becomes 0.67
1/4 becomes 0.25
5/6 becomes 0.83
0.25 or 1/4 is the least, followed by 0.5 or 1/2, 0.67 or 2/3, and finally 0.83 or 5/6
The order is 1/4, 1/2, 2/3, 5/6