1) \(\frac{5}{6}+\frac{2}{7};\) 2) \(\frac{11}{25}-\frac{3}{10};\) 3) \(\frac{15}{16}-\frac{3}{4};\) 4) \(\frac{3}{20}+\frac{7}{15};\) 5) \(\frac{13}{16}-\frac{7}{12};\) 6) \(\frac{9}{14}+\frac{5}{21};\) 7) \(\frac{16}{35}-\frac{5}{14};\) 8) \(\frac{2}{5}+\frac{1}{3}-\frac{7}{30};\) 9) \(\frac{3}{4}-\frac{2}{9}+\frac{5}{36};\)

Решим примеры:

1. $$ \frac{5}{6}+\frac{2}{7}=\frac{5 \cdot 7 + 2 \cdot 6}{42}=\frac{35+12}{42}=\frac{47}{42}=1\frac{5}{42} $$
2. $$ \frac{11}{25}-\frac{3}{10}=\frac{11 \cdot 2 - 3 \cdot 5}{50}=\frac{22-15}{50}=\frac{7}{50} $$
3. $$ \frac{15}{16}-\frac{3}{4}=\frac{15-3 \cdot 4}{16}=\frac{15-12}{16}=\frac{3}{16} $$
4. $$ \frac{3}{20}+\frac{7}{15}=\frac{3 \cdot 3 + 7 \cdot 4}{60}=\frac{9+28}{60}=\frac{37}{60} $$
5. $$ \frac{13}{16}-\frac{7}{12}=\frac{13 \cdot 3 - 7 \cdot 4}{48}=\frac{39-28}{48}=\frac{11}{48} $$
6. $$ \frac{9}{14}+\frac{5}{21}=\frac{9 \cdot 3 + 5 \cdot 2}{42}=\frac{27+10}{42}=\frac{37}{42} $$
7. $$ \frac{16}{35}-\frac{5}{14}=\frac{16 \cdot 2 - 5 \cdot 5}{70}=\frac{32-25}{70}=\frac{7}{70}=\frac{1}{10} $$
8. $$ \frac{2}{5}+\frac{1}{3}-\frac{7}{30}=\frac{2 \cdot 6 + 1 \cdot 10 - 7}{30}=\frac{12+10-7}{30}=\frac{15}{30}=\frac{1}{2} $$
9. $$ \frac{3}{4}-\frac{2}{9}+\frac{5}{36}=\frac{3 \cdot 9 - 2 \cdot 4 + 5}{36}=\frac{27-8+5}{36}=\frac{24}{36}=\frac{2}{3} $$

Ответ: 1) \(1\frac{5}{42}\); 2) \(\frac{7}{50}\); 3) \(\frac{3}{16}\); 4) \(\frac{37}{60}\); 5) \(\frac{11}{48}\); 6) \(\frac{37}{42}\); 7) \(\frac{1}{10}\); 8) \(\frac{1}{2}\); 9) \(\frac{2}{3}\)