| $$ \begin{aligned}\sqrt{5}\cdot\sqrt{5}& \xlongequal{ }\sqrt{25} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}5\end{aligned} $$ | |
| ① | The square root of $ 25 $ is $ 5 $. |