
\begin{enumerate}
\item $\begin{aligned}[t]
x & =\numprint{0,718718718}\ldots\\
\iff \numprint{1000}x & =\numprint{1000}\times\numprint{0,718718718}\ldots\\
 \iff \numprint{1000}x & =\numprint{718,718718718}\ldots\\
 \iff \numprint{1000}x & = 718 + \numprint{0,718718718}\ldots\\
\iff \numprint{1000}x & = 718 +x
\end{aligned}$

\item $\begin{aligned}[t]
\numprint{1000}x & = 718 +x
\iff \numprint{1000}x-x&=718\\
\iff 999x & = 718\\
\iff x & =\dfrac{718}{999}.
\end{aligned}$
\end{enumerate}
