\[- 1\frac{1}{80}\ :1,35 = - \frac{81}{80}\ :\frac{135}{100} =\]
\[= - \frac{81}{80}\ :\frac{27}{20} = - \frac{81}{80} \cdot \frac{20}{27} =\]
\[= - \frac{3}{4} = - 0,75.\]