| $$ \begin{aligned}12c-8-2c+10-4& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}10c-2\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{12c} \color{red}{-8} \color{blue}{-2c} + \color{green}{10} \color{green}{-4} = \color{blue}{10c} \color{green}{-2} $$ |