| $$ \begin{aligned}5 \cdot \frac{\sqrt{3}}{3}\cdot2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{10\sqrt{3}}{3}\end{aligned} $$ | |
| ① | $$ \color{blue}{ 5 \sqrt{3} } \cdot 2 = 10 \sqrt{3} $$$$ \color{blue}{ 3 } \cdot 1 = 3 $$ |