
\begin{enumerate}
\begin{multicols}{2}
\item $\begin{aligned}[t]
\left|\dfrac{1}{2}-\dfrac{1}{3}\right| & = \left|\dfrac{3}{6}-\dfrac{2}{6}\right|\\
& = \left|\dfrac{1}{6}\right|\\
\Aboxed{\left|\dfrac{1}{2}-\dfrac{1}{3}\right|& = \dfrac{1}{6}}
\end{aligned}$

\item $\begin{aligned}[t]
\left|\dfrac{1}{5}-\dfrac{1}{3}\right| & = \left|\dfrac{3}{15}-\dfrac{5}{15}\right|\\
& = \left|-\dfrac{2}{15}\right|\\
\Aboxed{\left|\dfrac{1}{5}-\dfrac{1}{3}\right| &  = \dfrac{2}{15}}
\end{aligned}$

\item $\begin{aligned}[t]
\left|\dfrac{2}{7}-\dfrac{7}{2}\right| & = \left|\dfrac{4}{14}-\dfrac{49}{14}\right| \\
& = \left|-\dfrac{45}{14}\right| \\
\Aboxed{\left|\dfrac{2}{7}-\dfrac{7}{2}\right| & = \dfrac{45}{14}}
\end{aligned}$

\item $\begin{aligned}[t]
\left|\dfrac{2}{3}-\dfrac{2}{5}\right| & = \left|\dfrac{10}{15}-\dfrac{6}{15}\right|\\
& = \left|\dfrac{4}{15}\right|\\
\Aboxed{\left|\dfrac{2}{3}-\dfrac{2}{5}\right| & = \dfrac{4}{15}}
\end{aligned}$
\end{multicols}
\end{enumerate}
