13. (6 points) There are 6 numbers arranged in a row, their average is 27, it is known that the average of the first 4 numbers is 23, the average of the last 3 numbers is 34, the 4th number is $\qquad$ .


【Answer】Solution: $23 \times 4+34 \times 3-27 \times 6$,
$$
\begin{array}{l}
=92+102-162, \\
=194-162, \\
=32 .
\end{array}
$$

Answer: The 4th number is 32.
Therefore, the answer is: 32.