Calcul (nombres naturels)

$$\begin{array}{rrrrrr} & {\small\color{red}{}} & {\small\color{red}{}} & {\small\color{red}{8}} & {\small\color{red}{10}}\\ & 1 & 9 & \color{gray}{9} & \color{gray}{0}\\ - & 1 & 6 & 1 & 2\\ \hline & 0 & 3 & 7 & 8\\ \end{array}$$

Nouvel exemple