Let $t \mapsto |t|$ be the D412: Absolute value function.
Let $x, a \in \mathbb{R}$ each be a D993: Real number.
Let $x, a \in \mathbb{R}$ each be a D993: Real number.
Then $|x| < a$ if and only if
\begin{equation}
x > -a
\quad \text{ and } \quad
x < a
\end{equation}