| $$ \begin{aligned}7\sqrt{16}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}7\cdot4 \xlongequal{ } \\[1 em] & \xlongequal{ }28\end{aligned} $$ | |
| ① | The square root of $ 16 $ is $ 4 $. |