Решение:
7$$\frac{3}{8}$$ - b + 4$$\frac{7}{15}$$ + b - 7$$\frac{3}{8}$$ - 2$$\frac{4}{5}$$ = (7$$\frac{3}{8}$$ - 7$$\frac{3}{8}$$) + (-b + b) + (4$$\frac{7}{15}$$ - 2$$\frac{4}{5}$$) = 0 + 0 + (4$$\frac{7}{15}$$ - 2$$\frac{12}{15}$$) = 4$$\frac{7}{15}$$ - 2$$\frac{12}{15}$$ = 3$$\frac{22}{15}$$ - 2$$\frac{12}{15}$$ = 1$$\frac{10}{15}$$ = 1$$\frac{2}{3}$$
**Ответ: 1$$\frac{2}{3}$$**