\[\boxed{\text{6.135.}}\]
\[\textbf{а)}\ 8,263 \approx 8;\ \ \ \ \ \ \ \ \ \ \ \ \ \ \]
\[0,13 \approx 0;\]
\[7,5303 \approx 8.\ \]
\[\textbf{б)}\ 12,612 \approx 10\ \ \ \ \ \ \ \ \ \]
\[10,5 \approx 11;\]
\[42,09 \approx 40;\]
\[74,2 \approx 70.\]