3) $$0,815·(-\frac{2}{3})-\frac{1}{6}·(-4,385)+0,815·\frac{1}{6}·(-4,385)·(-\frac{2}{3})$$

3) Выполним действия:

1) $$0,815 \cdot \left(-\frac{2}{3}\right) = \frac{815}{1000} \cdot \left(-\frac{2}{3}\right) = \frac{163}{200} \cdot \left(-\frac{2}{3}\right) = \frac{163}{100} \cdot \left(-\frac{1}{3}\right) = -\frac{163}{300}$$

2) $$\frac{1}{6} \cdot (-4,385) = \frac{1}{6} \cdot \left(-\frac{4385}{1000}\right) = \frac{1}{6} \cdot \left(-\frac{877}{200}\right) = -\frac{877}{1200}$$

3) $$\left(-\frac{163}{300}\right) - \left(-\frac{877}{1200}\right) = -\frac{163}{300} + \frac{877}{1200} = \frac{-163 \cdot 4}{300 \cdot 4} + \frac{877}{1200} = \frac{-652}{1200} + \frac{877}{1200} = \frac{225}{1200} = \frac{9}{48} = \frac{3}{16}$$

4) $$0,815 \cdot \frac{1}{6} = \frac{815}{1000} \cdot \frac{1}{6} = \frac{163}{200} \cdot \frac{1}{6} = \frac{163}{1200}$$

5) $$\frac{163}{1200} \cdot (-4,385) = \frac{163}{1200} \cdot \left(-\frac{4385}{1000}\right) = \frac{163}{1200} \cdot \left(-\frac{877}{200}\right) = -\frac{143}{1200} \cdot \frac{877}{200} = -\frac{142951}{240000}$$

6) $$\left(-\frac{142951}{240000}\right) \cdot \left(-\frac{2}{3}\right) = \frac{142951}{240000} \cdot \frac{2}{3} = \frac{142951}{120000} \cdot \frac{1}{3} = \frac{142951}{360000}$$

7) $$\frac{3}{16} + \frac{142951}{360000} = \frac{3 \cdot 22500}{16 \cdot 22500} + \frac{142951}{360000} = \frac{67500}{360000} + \frac{142951}{360000} = \frac{210451}{360000}$$

Ответ: $$\frac{210451}{360000}$$