Calcul (nombres naturels)

$$\begin{array}{rrrrrr} & {\small\color{red}{1}} & {\small\color{red}{}} & {\small\color{red}{1}} & {\small\color{red}{1}} & {\small\color{red}{}}\\ & & 5 & 7 & 8 & 6\\ + & & 8 & 0 & 2 & 5\\ \hline & 1 & 3 & 8 & 1 & 1\\ \end{array}$$

Nouvel exemple