66. Вычислите значение выражения наиболее удобным способом: 1) $$4 \frac{2}{7} \cdot 2 \frac{4}{9} + 1 \frac{2}{7} \cdot 2 \frac{4}{9}$$; 2) $$2 \frac{5}{6} \cdot 6 \frac{2}{3} + 6 \cdot 6 \frac{2}{3} - 6 \frac{2}{3} \cdot 1 \frac{1}{3}$$.

1) $$4 \frac{2}{7} \cdot 2 \frac{4}{9} + 1 \frac{2}{7} \cdot 2 \frac{4}{9} = (4 \frac{2}{7} + 1 \frac{2}{7}) \cdot 2 \frac{4}{9} = 5 \frac{4}{7} \cdot 2 \frac{4}{9} = \frac{39}{7} \cdot \frac{22}{9} = \frac{39 \cdot 22}{7 \cdot 9} = \frac{13 \cdot 3 \cdot 22}{7 \cdot 3 \cdot 3} = \frac{13 \cdot 22}{7 \cdot 3} = \frac{286}{21} = 13 \frac{13}{21}$$ 2) $$2 \frac{5}{6} \cdot 6 \frac{2}{3} + 6 \cdot 6 \frac{2}{3} - 6 \frac{2}{3} \cdot 1 \frac{1}{3} = 6 \frac{2}{3} \cdot (2 \frac{5}{6} + 6 - 1 \frac{1}{3}) = \frac{20}{3} \cdot (2 + 6 - 1 + \frac{5}{6} - \frac{1}{3}) = \frac{20}{3} \cdot (7 + \frac{5}{6} - \frac{2}{6}) = \frac{20}{3} \cdot (7 + \frac{3}{6}) = \frac{20}{3} \cdot (7 + \frac{1}{2}) = \frac{20}{3} \cdot \frac{15}{2} = \frac{20 \cdot 15}{3 \cdot 2} = \frac{10 \cdot 5}{1} = 50$$