             always the case.
            </p>

            <div class="practice">
                <p>
                    <strong>Example:</strong>
                    Consider $z_1 = -1$ and $z_2=i.$ Then
                    \[
                    \Arg\left(z_1z_2\right) = \Arg(-i)=-\frac{\pi}{2}
                    \]
                    but
                    \[
                    \Arg\left(z_1\right)+\Arg\left(z_2\right) = \pi +\frac{\pi}{2}= \frac{3\pi}{2}.
                    \]
                   