To find the numerical equivalent of \( 9^{9} \cdot 9^{-6} \), we can use the properties of exponents.
We apply the property that states \( a^m \cdot a^n = a^{m+n} \):
\[ 9^{9} \cdot 9^{-6} = 9^{9 - 6} = 9^{3} \]
Next, we calculate \( 9^{3} \):
\[ 9^{3} = 9 \cdot 9 \cdot 9 \]
Calculating this step-by-step:
- First calculate \( 9 \cdot 9 = 81 \).
- Then multiply the result by 9: \( 81 \cdot 9 \).
Now, calculating \( 81 \cdot 9 \):
\[ 81 \cdot 9 = 729 \]
Thus, the numerical equivalent of \( 9^{9} \cdot 9^{-6} \) is
\[ \boxed{729} \]