【Example 2】How many six-digit numbers can be formed using three odd numbers, two 2s, and one 8?
Solve for the total number of such six-digit numbers:
$$
\left(\begin{array}{lll}
6 & \\
3 & 2 & 1
\end{array}\right) \cdot 5^{3}=6!\cdot(3!\cdot 2!\cdot 1!)^{-1} \cdot 5^{3}=7500 \text { (numbers) }
$$