Выполняем сложение смешанных чисел:

1. $$3\frac{2}{7} + 5\frac{3}{14} = 3\frac{4}{14} + 5\frac{3}{14} = (3 + 5) + (\frac{4}{14} + \frac{3}{14}) = 8 + \frac{7}{14} = 8 + \frac{1}{2} = 8\frac{1}{2}$$
   Ответ: $$8\frac{1}{2}$$
2. $$5\frac{7}{8} + 2\frac{5}{12} = 5\frac{21}{24} + 2\frac{10}{24} = (5 + 2) + (\frac{21}{24} + \frac{10}{24}) = 7 + \frac{31}{24} = 7 + 1\frac{7}{24} = 8\frac{7}{24}$$
   Ответ: $$8\frac{7}{24}$$
3. $$7\frac{3}{8} + 1\frac{5}{6} = 7\frac{9}{24} + 1\frac{20}{24} = (7 + 1) + (\frac{9}{24} + \frac{20}{24}) = 8 + \frac{29}{24} = 8 + 1\frac{5}{24} = 9\frac{5}{24}$$
   Ответ: $$9\frac{5}{24}$$
4. $$1\frac{1}{9} + 2\frac{3}{5} = 1\frac{5}{45} + 2\frac{27}{45} = (1 + 2) + (\frac{5}{45} + \frac{27}{45}) = 3 + \frac{32}{45} = 3\frac{32}{45}$$
   Ответ: $$3\frac{32}{45}$$
5. $$7\frac{2}{9} + 4 = (7 + 4) + \frac{2}{9} = 11 + \frac{2}{9} = 11\frac{2}{9}$$
   Ответ: $$11\frac{2}{9}$$
6. $$8\frac{3}{5} + \frac{1}{15} = 8\frac{9}{15} + \frac{1}{15} = 8 + \frac{10}{15} = 8 + \frac{2}{3} = 8\frac{2}{3}$$
   Ответ: $$8\frac{2}{3}$$
7. $$7 + 3\frac{5}{8} = (7 + 3) + \frac{5}{8} = 10 + \frac{5}{8} = 10\frac{5}{8}$$
   Ответ: $$10\frac{5}{8}$$
8. $$\frac{2}{3} + 4\frac{3}{5} = \frac{10}{15} + 4\frac{9}{15} = 4 + (\frac{10}{15} + \frac{9}{15}) = 4 + \frac{19}{15} = 4 + 1\frac{4}{15} = 5\frac{4}{15}$$
   Ответ: $$5\frac{4}{15}$$