\[\{ 0,\ 1,\ 2,\ 3,\ 4,\ 5,\ 6,\ 7,\ 8,\ 9\}\]
\[C_{9}^{4} = \frac{9!}{4! \cdot 5!} = \frac{6 \cdot 7 \cdot 8 \cdot 9}{2 \cdot 3 \cdot 4} =\]
\[= 3 \cdot 7 \cdot 2 \cdot 3 = 126.\]
\[Ответ:126\ номеров.\]