$$ \begin{aligned}7^3\cdot7^4& \xlongequal{ }343\cdot2401 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}823543\end{aligned} $$ | |
① | $ 343 \cdot 2401 = 823543 $ |