\[53\ :3\frac{8}{15} - 15,8 + 1\frac{5}{11} =\]
\[= \frac{53}{1}\ :\frac{53}{15} - 15,8 + \frac{16}{11} =\]
\[= \frac{53}{1} \cdot \frac{15}{53} - 15,8 + \frac{16}{11} =\]
\[= 15 - 15,8 + \frac{16}{11} = - 0,8 + \frac{16}{11} =\]
\[= \frac{16^{\backslash 10}}{11} - \frac{8^{\backslash 11}}{10} = \frac{160 - 88}{110} = \frac{72}{100} = \frac{36}{55}\]