Reken uit
- \(55 + 40 = \ldots\)
- \(40 + 21 = \ldots\)
- \(41 + 30 = \ldots\)
- \(10 + 23 = \ldots\)
- \(30 + 45 = \ldots\)
- \(10 + 17 = \ldots\)
- \(36 + 20 = \ldots\)
- \(10 + 46 = \ldots\)
- \(77 + 10 = \ldots\)
- \(69 + 20 = \ldots\)
- \(10 + 36 = \ldots\)
- \(78 + 10 = \ldots\)
Reken uit
Verbetersleutel
- \(\begin{align} & 55 + 40 \\
= & 40 + 55 \\= & 40 + \color{green}{50} + \color{red}{5} \\
= & \color{green}{90} + \color{red}{5} \\
= & \color{red}{95} \end{align}\)
- \(\begin{align} & 40 + 21 \\= & 40 + \color{green}{20} + \color{red}{1} \\
= & \color{green}{60} + \color{red}{1} \\
= & \color{red}{61} \end{align}\)
- \(\begin{align} & 41 + 30 \\
= & 30 + 41 \\= & 30 + \color{green}{40} + \color{red}{1} \\
= & \color{green}{70} + \color{red}{1} \\
= & \color{red}{71} \end{align}\)
- \(\begin{align} & 10 + 23 \\= & 10 + \color{green}{20} + \color{red}{3} \\
= & \color{green}{30} + \color{red}{3} \\
= & \color{red}{33} \end{align}\)
- \(\begin{align} & 30 + 45 \\= & 30 + \color{green}{40} + \color{red}{5} \\
= & \color{green}{70} + \color{red}{5} \\
= & \color{red}{75} \end{align}\)
- \(\begin{align} & 10 + 17 \\= & 10 + \color{green}{10} + \color{red}{7} \\
= & \color{green}{20} + \color{red}{7} \\
= & \color{red}{27} \end{align}\)
- \(\begin{align} & 36 + 20 \\
= & 20 + 36 \\= & 20 + \color{green}{30} + \color{red}{6} \\
= & \color{green}{50} + \color{red}{6} \\
= & \color{red}{56} \end{align}\)
- \(\begin{align} & 10 + 46 \\= & 10 + \color{green}{40} + \color{red}{6} \\
= & \color{green}{50} + \color{red}{6} \\
= & \color{red}{56} \end{align}\)
- \(\begin{align} & 77 + 10 \\
= & 10 + 77 \\= & 10 + \color{green}{70} + \color{red}{7} \\
= & \color{green}{80} + \color{red}{7} \\
= & \color{red}{87} \end{align}\)
- \(\begin{align} & 69 + 20 \\
= & 20 + 69 \\= & 20 + \color{green}{60} + \color{red}{9} \\
= & \color{green}{80} + \color{red}{9} \\
= & \color{red}{89} \end{align}\)
- \(\begin{align} & 10 + 36 \\= & 10 + \color{green}{30} + \color{red}{6} \\
= & \color{green}{40} + \color{red}{6} \\
= & \color{red}{46} \end{align}\)
- \(\begin{align} & 78 + 10 \\
= & 10 + 78 \\= & 10 + \color{green}{70} + \color{red}{8} \\
= & \color{green}{80} + \color{red}{8} \\
= & \color{red}{88} \end{align}\)