| $$ \begin{aligned}2+40g+72& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}40g+74\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{2} +40g+ \color{blue}{72} = 40g+ \color{blue}{74} $$ |