$$\frac{3\ 4}{5} \times \frac{2\ 1}{3} = \left(3 + \frac{4}{5}\right) \times \left(2 + \frac{1}{3}\right) = 3 \times 2 + 3 \times \frac{1}{3} + \frac{4}{5} \times 2 + \frac{4}{5} \times \frac{1}{3} = 6 + 1 + \frac{8}{5} + \frac{4}{15} = 7 + \frac{8}{5} + \frac{4}{15} = 7 + \frac{24 + 4}{15} = 7 + \frac{28}{15} = 7\ \frac{13}{15}$$
Итак, $\frac{3\ 4}{5} \times \frac{2\ 1}{3} = 7\ \frac{13}{15}$.
$$\frac{3\ 4}{5} \times \frac{2\ 1}{3} = \left(3 + \frac{4}{5}\right) \times \left(2 + \frac{1}{3}\right) = 3 \times 2 + 3 \times \frac{1}{3} + \frac{4}{5} \times 2 + \frac{4}{5} \times \frac{1}{3} = 6 + 1 + \frac{8}{5} + \frac{4}{15} = 7 + \frac{8}{5} + \frac{4}{15} = 7 + \frac{24 + 4}{15} = 7 + \frac{28}{15} = 7\ \frac{13}{15}$$
Итак, $\frac{3\ 4}{5} \times \frac{2\ 1}{3} = 7\ \frac{13}{15}$.