Выполните действия:
а) $8\frac{1}{3} + 6\frac{1}{2} - 3\frac{5}{6} = 11$
1) $8\frac{1}{3} + 6\frac{1}{2} = 8 + \frac{2}{6} + 6 + \frac{3}{6} = 14 + \frac{5}{6} = 14\frac{5}{6}$;
2) $14\frac{5}{6} - 3\frac{5}{6} = 11$.

б) $12\frac{3}{8} - 5\frac{1}{4} + 7\frac{1}{2} = 14\frac{5}{8}$
1) $12\frac{3}{8} - 5\frac{1}{4} = 12\frac{3}{8} - 5\frac{2}{8} = 7\frac{1}{8}$;
2) $7\frac{1}{8} + 7\frac{1}{2} = 7 + \frac{1}{8} + 7 + \frac{4}{8} = 14 + \frac{5}{8} = 14\frac{5}{8}$.

в) $2\frac{1}{3} \cdot \frac{3}{10} : 2\frac{4}{5} = \frac{1}{4} = 0,25$
1) $2\frac{1}{3} \cdot \frac{3}{10} = \frac{7}{3} \cdot \frac{3}{10} = \frac{7 \cdot 3}{3  \cdot 10} = \frac{7 \cdot 1}{1 \cdot 10} =  \frac{7}{10} = 0,7$;
2) $\frac{7}{10} : 2\frac{4}{5} = \frac{7}{10} : \frac{14}{5} = \frac{7}{10} \cdot \frac{5}{14} = \frac{7 \cdot 5}{10 \cdot 14} = \frac{1 \cdot 1}{2 \cdot 2} = \frac{1}{4}$.

г) $1\frac{1}{6} : 2\frac{1}{6} \cdot 26 = \frac{1}{4} = 14$
1) $1\frac{1}{6} : 2\frac{1}{6} = \frac{7}{6} : \frac{13}{6} = \frac{7}{6} \cdot \frac{6}{13} = \frac{7 \cdot 6}{6 \cdot 13} = \frac{7 \cdot 1}{1 \cdot 13} = \frac{7}{13}$;
2) $\frac{7}{13} \cdot 26 = 7 \cdot 2 = 14$.