a) $$ \frac{5}{7} + \frac{1}{7} = \frac{\textbf{6}}{7}$$
б) $$ \frac{3}{8} + \frac{2}{8} = \frac{\textbf{5}}{8}$$
в) $$ \frac{4}{11} + \frac{5}{11} = \frac{\textbf{9}}{11}$$
г) $$ \frac{5}{6} - \frac{3}{6} = \frac{\textbf{2}}{6}$$
д) $$ \frac{3}{4} - \frac{2}{4} = \frac{\textbf{1}}{4}$$
e) $$ \frac{5}{10} - \frac{5}{10} = \frac{\textbf{0}}{10} = ...$$
Ответ: a) $$\frac{6}{7}$$, б) $$\frac{5}{8}$$, в) $$\frac{9}{11}$$, г) $$\frac{2}{6}$$, д) $$\frac{1}{4}$$, e) $$0$$