\[\boxed{\mathbf{883}.}\]
\[1)\log_{8}7 =\]
\[= \frac{\ln 7}{\ln 8} \approx \frac{1,94591}{2,07944} \approx 0,93578\]
\[2)\log_{3}12 =\]
\[= \frac{\ln 12}{\ln 3} \approx \frac{2,48491}{1,09861} \approx 2,26186\]
\[3)\log_{1,3}{0,17} =\]
\[= \frac{\ln{0,17}}{\ln{1,3}} \approx \frac{- 1,77196}{0,26236} \approx - 6,75392\]
\[4)\log_{0,3}{8,1} =\]
\[= \frac{\ln{8,1}}{\ln{0,3}} \approx \frac{2,09186}{- 1,20397} \approx - 1,73746\]