<div class="exemple">
\def{real a=randint(1..10)/2}
\def{real b=-randint(1..10)/2}
\def{real b1=-(\b)}
\def{ireal s=\a-\b}
\def{real sp=\a-\b}
<center>
   \( \begin{array}{ccl}
        A & = & \a-(\b)  \\
        A & = & \a+(+\b1)  \\
	A & = & \a+\b1 \\
        A & = & \s
\end{array})&nbsp;&nbsp;&nbsp;
\def{real a=-randint(1..10)/2}
\def{real b=-randint(1..10)/2}
\def{real b1=-(\b)}
\def{real s=\a-\b}
\(\begin{array}{ccl}   
        B & = & \a-(\b)  \\
        B & = & \a+(+\b1)  \\
	B & = & \a+\b1  \\
        B & = & \s
\end{array})
&nbsp;&nbsp;&nbsp;
\def{real a=randint(1..10)/2}
\def{real b=randint(1..10)/2}
\def{real s=\a-\b}
 \(\begin{array}{ccl} 
        D & = & \a-(+\b)  \\
        D & = & \a+(-\b)  \\
        D & = & \a-\b  \\
        D & = & \s
    \end{array} )

</center>
</div>


<div class="aide"><span class="aide">Sobre la escritura simplificada: </span>
    Con el hbito se pasa directamente de la primera a la 
    tercera lnea de cada clculo.
</div>
