Addition of Codewords in Linear Code/Examples/V(2,3)

Example of Addition of Codewords in $V \paren {2, 3}$
In the master code $V \paren {2, 3}$, the codewords $12$ and $11$ are added thus:
 * $12 + 11 = 20$

Proof
Taking the elements of $12$ and $11$ in pairs, successively, we have:

Hence the result.