| $$ \begin{aligned}\sqrt{1}+4^4& \xlongequal{ }1+4^4 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}1+256 \xlongequal{ } \\[1 em] & \xlongequal{ }257\end{aligned} $$ | |
| ① | $ 4 ^ 4 = 256 $ |