11. (5 points) Use small cubes with edge length $m$ to form a large cube with edge length 12. Now paint the surface (6 faces) of the large cube red. If the number of small cubes with only one red face is equal to the number of small cubes with only two red faces, then $m=$ $\qquad$ .
【Solution】Solution: According to the problem, there are $12 \div m$ small cubes on each edge of the large cube. Let $12 \div m=n$, which means there are $n$ small cubes on each edge of the large cube,
$$
\begin{array}{c}
6(n-2)^{2}=12(n-2) \\
(n-2)^{2}=2(n-2) \\
n-2=2 \\
n=4
\end{array}
$$

Since $12 \div m=4$
Therefore, $m=3$
Answer: $m=3$.
So the answer is: 3.