Brug over tiental

Reken uit

\(79 + 5 = \ldots\)

\(\begin{align} & 79 + 5 \\= & 79 + \color{green}{1} + \color{red}{4} \\= & \color{green}{80} + \color{red}{4} \\= & \color{red}{84} \end{align}\)