\[\text{tg}\frac{\pi}{4} \cdot ctg\frac{3\pi}{4} + tg\frac{\pi}{6} \cdot ctg\frac{5\pi}{6} =\]
\[= 1 \cdot ( - 1) + \frac{1}{\sqrt{3}} \cdot \left( - \frac{1}{\sqrt{3}} \right) =\]
\[= - 1 - \frac{1}{3} = - 1\frac{1}{3}\]