Can fractions be written with a one under them and can problems be solved this way

Question

How would you write $\frac{a}{0.1}$?

Are either of these ways acceptable?

$$ \frac{\frac{a}{1}}{\frac{\frac{1}{10}}{1}} = \frac{a}{1} \times \frac{1}{\frac{1}{10}} $$ or $$ \frac{\frac{a}{1}}{\frac{1}{10}} = \frac{a}{1} \times \frac{10}{1} $$

Answer 1

Both expressions are correct and yield $10a$ in the completely simplified form.