Решение:
1. $$\frac{16}{15} : \frac{2}{5} = \frac{16}{15} \cdot \frac{5}{2} = \frac{16 \cdot 5}{15 \cdot 2} = \frac{80}{30} = \frac{8}{3} = 2\frac{2}{3}$$
2. $$6\frac{1}{3} = \frac{6 \cdot 3 + 1}{3} = \frac{19}{3}$$
3. $$2\frac{1}{12} = \frac{2 \cdot 12 + 1}{12} = \frac{25}{12}$$
4. $$\frac{25}{12} \cdot \frac{4}{5} = \frac{25 \cdot 4}{12 \cdot 5} = \frac{100}{60} = \frac{5}{3} = 1\frac{2}{3}$$
5. $$2\frac{2}{3} - 6\frac{1}{3} + 1\frac{2}{3} = \frac{8}{3} - \frac{19}{3} + \frac{5}{3} = \frac{8 - 19 + 5}{3} = \frac{-6}{3} = -2$$
Ответ: -2