10. (3 points) The greatest common divisor and the least common multiple of two numbers are 3 and 135, respectively. Find the minimum difference between these two numbers is $\qquad$ .
【Solution】Solution: Since $135 \div 3=45, 45$ can be decomposed into two coprime numbers in two ways, which are 1 and $45$, 9 and 5, so the pair with the smallest difference is: 9 and 5,

Therefore, these two numbers are:
$$
\begin{array}{l}
9 \times 3=27 \\
5 \times 3=15 \\
27-15=12
\end{array}
$$

Answer: The smallest difference between these two numbers is 12.
Therefore, the answer is: 12.