0.999...=1

$$ \large\begin{align*} \frac{1}{3} &= 0.\stackrel{\frown}{3} \\ \frac{1}{3} &= 0.333\dots \\ 3 \cdot \frac{1}{3} &= 3 \cdot 0.333\dots \\ 1 &= 0.999\dots \\ 1 &= 0.\stackrel{\frown}{9} \end{align*} $$