1) $$6 \frac{3}{5} \cdot 4 \frac{1}{6} - 2 \frac{1}{6} \cdot 6 \frac{3}{5} = 6 \frac{3}{5} \cdot (4 \frac{1}{6} - 2 \frac{1}{6}) = 6 \frac{3}{5} \cdot (4 - 2 + \frac{1}{6} - \frac{1}{6}) = 6 \frac{3}{5} \cdot 2 = \frac{33}{5} \cdot 2 = \frac{66}{5} = 13 \frac{1}{5}$$
Ответ: 13 1/5