Brug Mix (reeks 2)

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\(55 + 15 = \ldots\)

\(\begin{align} & 55 + 15\\= & \color{green}{50} + \color{red}{5} + \color{green}{10} + \color{red}{5} \\= & \color{green}{60} + \color{red}{10} \\= & \color{red}{70} \end{align}\)