Reken uit
- \(20 + 58 = \ldots\)
- \(10 + 59 = \ldots\)
- \(49 + 30 = \ldots\)
- \(30 + 44 = \ldots\)
- \(18 + 60 = \ldots\)
- \(20 + 34 = \ldots\)
- \(58 + 10 = \ldots\)
- \(15 + 30 = \ldots\)
- \(81 + 10 = \ldots\)
- \(20 + 15 = \ldots\)
- \(30 + 36 = \ldots\)
- \(66 + 30 = \ldots\)
Reken uit
Verbetersleutel
- \(\begin{align} & 20 + 58 \\= & 20 + \color{green}{50} + \color{red}{8} \\
= & \color{green}{70} + \color{red}{8} \\
= & \color{red}{78} \end{align}\)
- \(\begin{align} & 10 + 59 \\= & 10 + \color{green}{50} + \color{red}{9} \\
= & \color{green}{60} + \color{red}{9} \\
= & \color{red}{69} \end{align}\)
- \(\begin{align} & 49 + 30 \\
= & 30 + 49 \\= & 30 + \color{green}{40} + \color{red}{9} \\
= & \color{green}{70} + \color{red}{9} \\
= & \color{red}{79} \end{align}\)
- \(\begin{align} & 30 + 44 \\= & 30 + \color{green}{40} + \color{red}{4} \\
= & \color{green}{70} + \color{red}{4} \\
= & \color{red}{74} \end{align}\)
- \(\begin{align} & 18 + 60 \\
= & 60 + 18 \\= & 60 + \color{green}{10} + \color{red}{8} \\
= & \color{green}{70} + \color{red}{8} \\
= & \color{red}{78} \end{align}\)
- \(\begin{align} & 20 + 34 \\= & 20 + \color{green}{30} + \color{red}{4} \\
= & \color{green}{50} + \color{red}{4} \\
= & \color{red}{54} \end{align}\)
- \(\begin{align} & 58 + 10 \\
= & 10 + 58 \\= & 10 + \color{green}{50} + \color{red}{8} \\
= & \color{green}{60} + \color{red}{8} \\
= & \color{red}{68} \end{align}\)
- \(\begin{align} & 15 + 30 \\
= & 30 + 15 \\= & 30 + \color{green}{10} + \color{red}{5} \\
= & \color{green}{40} + \color{red}{5} \\
= & \color{red}{45} \end{align}\)
- \(\begin{align} & 81 + 10 \\
= & 10 + 81 \\= & 10 + \color{green}{80} + \color{red}{1} \\
= & \color{green}{90} + \color{red}{1} \\
= & \color{red}{91} \end{align}\)
- \(\begin{align} & 20 + 15 \\= & 20 + \color{green}{10} + \color{red}{5} \\
= & \color{green}{30} + \color{red}{5} \\
= & \color{red}{35} \end{align}\)
- \(\begin{align} & 30 + 36 \\= & 30 + \color{green}{30} + \color{red}{6} \\
= & \color{green}{60} + \color{red}{6} \\
= & \color{red}{66} \end{align}\)
- \(\begin{align} & 66 + 30 \\
= & 30 + 66 \\= & 30 + \color{green}{60} + \color{red}{6} \\
= & \color{green}{90} + \color{red}{6} \\
= & \color{red}{96} \end{align}\)