\[\boxed{\mathbf{16}\mathbf{.}}\]
\[1)\ 6 \cdot 2 = 12\]
\[8 \cdot 2 = 16\]
\[7 \cdot 2 = 14\]
\[9 \cdot 2 = 18\]
\[2)\ 8 \cdot 3 = 24\]
\[6 \cdot 3 = 18\]
\[9 \cdot 3 = 27\]
\[7 \cdot 3 = 21\]
\[3)\ 7 \cdot 4 = 28\]
\[9 \cdot 4 = 36\]
\[6 \cdot 4 = 24\]
\[8 \cdot 4 = 32\]