a) $$\frac{19}{7} = 2\frac{5}{7}$$
б) $$\frac{412}{10} = 41\frac{2}{10} = 41\frac{1}{5}$$
в) $$\frac{168}{8} = 21$$
Ответ: a) $$2\frac{5}{7}$$, б) $$41\frac{1}{5}$$, в) $$21$$