| $$ \begin{aligned}10sqrt\cdot3+10sqrt\cdot75& \xlongequal{ }30qrst+750qrst \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}780qrst\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{30qrst} + \color{blue}{750qrst} = \color{blue}{780qrst} $$ |