Calcul (nombres naturels)

$$\begin{array}{rrrrrrr} & {\small\color{orange}{}} & {\small\color{orange}{}} & {\small\color{orange}{}} & {\small\color{orange}{2}} & {\small\color{orange}{1}} & {\small\color{orange}{}}\\ & {\small\color{blue}{}} & {\small\color{blue}{}} & {\small\color{blue}{}} & {\small\color{blue}{5}} & {\small\color{blue}{2}} & {\small\color{blue}{}}\\ & {\small\color{red}{}} & {\small\color{red}{}} & {\small\color{red}{}} & {\small\color{red}{1}} & {\small\color{red}{}} & {\small\color{red}{}}\\ & & & & & 7 & 3 & 1\\ \cdot & & & & & \color{orange}{4} & \color{blue}{8} & \color{red}{2}\\ \hline & & \color{red}{} & \color{red}{} & \color{red}{1} & \color{red}{4} & \color{red}{6} & \color{red}{2}\\ & & \color{blue}{} & \color{blue}{5} & \color{blue}{8} & \color{blue}{4} & \color{blue}{8} & \color{blue}{0}\\ + & & \color{orange}{2} & \color{orange}{9} & \color{orange}{2} & \color{orange}{4} & \color{orange}{0} & \color{orange}{0}\\ \hline & & 3 & 5 & 2 & 3 & 4 & 2\\ \end{array}$$

Nouvel exemple