$$ \begin{aligned}\frac{\sqrt{1}}{\sqrt{1}\cdot39}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{1}{\sqrt{1}\cdot39}\end{aligned} $$ | |
① | The square root of $ 1 $ is $ 1 $. |