$$ \begin{aligned}\frac{10}{75}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}} \frac{ 10 : \color{orangered}{ 5 } }{ 75 : \color{orangered}{ 5 }} \xlongequal{ } \\[1 em] & \xlongequal{ }\frac{2}{15}\end{aligned} $$ | |
① | Divide both the top and bottom numbers by $ \color{orangered}{ 5 } $. |