\[\boxed{\mathbf{454.}}\]
\[20 \cdot 6 = 120\]
\[30 \cdot 7 = 210\]
\[40 \cdot 4 = 160\]
\[70 \cdot 2 = 140\]
\[50 \cdot 7 = 350\]
\[80 \cdot 3 = 240\]
\[30 \cdot 4 = 120\]
\[20 \cdot 8 = 160\]
\[60 \cdot 3 = 180\]
\[40 \cdot 6 = 240\]
\[70 \cdot 4 = 280\]
\[90 \cdot 6 = 540\]