| $$ \begin{aligned}\sqrt{\frac{25}{9}}& \xlongequal{ }\frac{1}{3}\sqrt{25} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{5}{3}\end{aligned} $$ | |
| ① | $$ \frac{ 1 }{ 3 } \sqrt{ 25 } = \frac{ 1 }{ 3 } \cdot 5 = \frac{ 5 }{ 3 } $$ |