\[5\frac{5^{\backslash 3}}{18} - 2\frac{10^{\backslash 2}}{27} = 5\frac{15}{54} - 2\frac{20}{54} =\]
\[= 4\frac{69}{54} - 2\frac{20}{54} = 2\frac{49}{54}.\]