\[\boxed{\mathbf{1.}}\]
\[6 \cdot 4 = 24\]
\[4 \cdot 6 = 24\]
\[6 + 6 + 6 + 6 = 24\]
\[5 \cdot 6 = 30\]
\[6 \cdot 5 = 30\]
\[6 + 6 + 6 + 6 + 6 = 30\]
\[2 \cdot 9 = 18\]
\[9 \cdot 2 = 18\]
\[9 + 9 = 18\]