codice:
_______
A and B
            ___
A B | A*B | A*B
----+-----+-----
0 0 |  0  |  1
0 1 |  0  |  1
1 0 |  0  |  1
1 1 |  1  |  0

_    _
A or B
      _   _   _ _
A B | A | B | A+B
----+---+---+----- 
0 0 | 1 | 1 |  1
0 1 | 1 | 0 |  1
1 0 | 0 | 1 |  1
1 1 | 0 | 0 |  0