Вычислите: (9/10–1/5)/(1/2).

\[\frac{\frac{9}{10} - \frac{1}{5}}{\frac{1}{2}} = \frac{\frac{9 - 2}{10}}{\frac{1}{2}} = \frac{7}{10}\ :\frac{1}{2} = \frac{7 \cdot 2}{10 \cdot 1} =\]

\[= \frac{7}{5} = 1\frac{2}{5}\]