How to make logical OR with AND,and NOT?

Question

How to create a logical OR with logical AND, and logical NOT?

Answer 1

It's De Morgan's Law:

A OR B = NOT ( NOT A AND NOT B )

Truth table for A OR B:

A B  X
0 0  0
0 1  1
1 0  1
1 1  1

Truth table for the De Morgan equivalent:

A B  !A  !B  (!A AND !B)   !(!A AND !B)
0 0   1   1       1              0
0 1   1   0       0              1
1 0   0   1       0              1
1 1   0   0       0              1