Basis Optellen

Reken uit

\(10 + 31 = \ldots\)

\(\begin{align} & 10 + 31 \\= & 10 + \color{green}{30} + \color{red}{1} \\ = & \color{green}{40} + \color{red}{1} \\ = & \color{red}{41} \end{align}\)