Решение:
\( \frac{3}{5} + 0,425 - 0,005 = \frac{3}{5} + \frac{425}{1000} - \frac{5}{1000} = 0.6 + 0.425 - 0.005 = 1.02 \)
\( 30,5 + \frac{1}{6} + 3\frac{1}{3} = 30.5 + \frac{1}{6} + \frac{10}{3} = \frac{61}{2} + \frac{1}{6} + \frac{10}{3} = \frac{183 + 1 + 20}{6} = \frac{204}{6} = 34 \)
\( \frac{1.02}{34} : 0.1 = \frac{1.02}{34} \cdot 10 = \frac{10.2}{34} = 0.3 \)
\( 6\frac{3}{4} + 5\frac{1}{2} = \frac{27}{4} + \frac{11}{2} = \frac{27 + 22}{4} = \frac{49}{4} = 12.25 \)
\( 0.3 + \frac{49}{4} - 0.05 = 0.3 + 12.25 - 0.05 = 12.55 - 0.05 = 12.5 \)
Ответ: 12.5