Найдем значение выражения:
$$\frac{6}{13} \cdot 19 \frac{1}{2} = \frac{6}{13} \cdot \frac{39}{2} = \frac{6 \cdot 39}{13 \cdot 2} = \frac{6 \cdot 3}{1 \cdot 2} = \frac{18}{2} = 9$$
$$\frac{10}{11} \cdot 3 \frac{1}{7} = \frac{10}{11} \cdot \frac{22}{7} = \frac{10 \cdot 22}{11 \cdot 7} = \frac{10 \cdot 2}{1 \cdot 7} = \frac{20}{7} = 2 \frac{6}{7}$$
$$0,4 \cdot 3 \frac{1}{3} = \frac{4}{10} \cdot \frac{10}{3} = \frac{4 \cdot 10}{10 \cdot 3} = \frac{4}{3} = 1 \frac{1}{3}$$
$$0,6 \cdot \frac{2}{3} = \frac{6}{10} \cdot \frac{2}{3} = \frac{6 \cdot 2}{10 \cdot 3} = \frac{2 \cdot 2}{10 \cdot 1} = \frac{4}{10} = 0,4$$
Ответ: 1) $$9$$, 2) $$2 \frac{6}{7}$$, 3) $$1 \frac{1}{3}$$, 4) $$0,4$$