Note that the question is asking for the order from greatest to least. In the case of decimals, I find it easier to compare by placing them in a line going down and filling in zeros where needed to make them the same place values:
2.256 - S
2.220 - T
2.099 - U
2.710 - V
Since they all have the same first digit, I will look at the next digit following the decimal. '7' is the greatest, then '25', then '22' then '09':
