7) 0,1 × 6 $$ \frac{1}{5} $$ = 0,1 × $$ \frac{6 \cdot 5 + 1}{5} $$ = 0,1 × $$ \frac{31}{5} $$ = $$ \frac{1}{10} $$ × $$ \frac{31}{5} $$ = $$ \frac{31}{50} $$
Ответ: $$ \frac{31}{50} $$