Find the mistake: two-step equations

Mia tried to solve an equation step by step. $\qquad\begin{align} 0.1t-3&=5\\\\ \\ 0.1t&=2&\green{\text{Step } 1}\\\\ \\ t&=20&\blue{\text{Step } 2}\\\\ \end{align}$ **Find Mia's mistake.** [[☃ radio 1]]