Calcul (nombres naturels)

$$\begin{array}{rrrrrrr} & {\small\color{orange}{}} & {\small\color{orange}{}} & {\small\color{orange}{}} & {\small\color{orange}{5}} & {\small\color{orange}{1}} & {\small\color{orange}{}}\\ & {\small\color{blue}{}} & {\small\color{blue}{}} & {\small\color{blue}{}} & {\small\color{blue}{1}} & {\small\color{blue}{}} & {\small\color{blue}{}}\\ & {\small\color{red}{}} & {\small\color{red}{}} & {\small\color{red}{}} & {\small\color{red}{}} & {\small\color{red}{}} & {\small\color{red}{}}\\ & & & & & 8 & 2 & 0\\ \cdot & & & & & \color{orange}{7} & \color{blue}{2} & \color{red}{1}\\ \hline & & \color{red}{} & \color{red}{} & \color{red}{} & \color{red}{8} & \color{red}{2} & \color{red}{0}\\ & & \color{blue}{} & \color{blue}{1} & \color{blue}{6} & \color{blue}{4} & \color{blue}{0} & \color{blue}{0}\\ + & & \color{orange}{5} & \color{orange}{7} & \color{orange}{4} & \color{orange}{0} & \color{orange}{0} & \color{orange}{0}\\ \hline & & 5 & 9 & 1 & 2 & 2 & 0\\ \end{array}$$

Nouvel exemple