\[3\frac{3}{7} \cdot 2\frac{2}{13} + 2\frac{1}{7} \cdot 2\frac{2}{13} =\]
\[= 2\frac{2}{13} \cdot \left( 3\frac{3}{7} + 2\frac{1}{7} \right) =\]
\[= 2\frac{2}{13} \cdot 5\frac{4}{7} = \frac{28 \cdot 39}{13 \cdot 7} = 12\]