\[\boxed{\text{5.500.}}\]
\[\textbf{а)}\ 27 + 36 = 63\ :7 = 9 + 51 =\]
\[= 60\ :30 = 2\]
\[\textbf{б)}\ 25 \cdot 11 = 275\ :25 =\]
\[= 11 - 36 = - 25\ :8 = - \frac{25}{8} =\]
\[= - 3\frac{1}{8}\]
\[\textbf{в)}\ 125 \cdot 2 = 250 + 17 =\]
\[= 267 - 15 = 252\ :9 = 28\]
\[\textbf{г)}\ 153\ :3 = 51 - 12 = 39 + 6 =\]
\[= 45\ :5 = 9\]