Выполним действия по порядку:
1) $$2\frac{5}{6} + \frac{7}{6} = \frac{17}{6} + \frac{7}{6} = \frac{17 + 7}{6} = \frac{24}{6} = 4$$
2) $$4 \cdot \frac{3}{5} = \frac{4 \cdot 3}{5} = \frac{12}{5}$$
3) $$\frac{8}{3} - \frac{12}{5} = \frac{8 \cdot 5}{3 \cdot 5} - \frac{12 \cdot 3}{5 \cdot 3} = \frac{40}{15} - \frac{36}{15} = \frac{40 - 36}{15} = \frac{4}{15}$$
4) $$1\frac{3}{22} - \frac{4}{15} = \frac{25}{22} - \frac{4}{15} = \frac{25 \cdot 15}{22 \cdot 15} - \frac{4 \cdot 22}{15 \cdot 22} = \frac{375}{330} - \frac{88}{330} = \frac{375 - 88}{330} = \frac{287}{330}$$
Ответ: $$\frac{287}{330}$$