6) 146-812;

$$14 \frac{6}{20} - 8 \frac{12}{20} = 13 \frac{26}{20} - 8 \frac{12}{20} = (13 - 8) + (\frac{26}{20} - \frac{12}{20}) = 5 + \frac{14}{20} = 5 + \frac{7}{10} = 5 \frac{7}{10}$$

Ответ: $$5 \frac{7}{10}$$