\[45\ :3\frac{6}{13} - 13,6 + 1\frac{3}{8} =\]
\[= \frac{45}{1}\ :\frac{45}{13} - 13,6 + 1\frac{3}{8} =\]
\[= 13 - 13,6 + 1\frac{3}{8} = - 0,6 + 1\frac{3}{8} =\]
\[= - \frac{3}{5} + \frac{11}{8} = \frac{55}{40} - \frac{24}{40} = \frac{31}{40}.\]