| $$ \begin{aligned}\frac{152}{209}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}} \frac{ 152 : \color{orangered}{ 19 } }{ 209 : \color{orangered}{ 19 }} \xlongequal{ } \\[1 em] & \xlongequal{ }\frac{8}{11}\end{aligned} $$ | |
| ① | Divide both the top and bottom numbers by $ \color{orangered}{ 19 } $. |