---snip--- Hi Actually from a mathematical sense, it does make sense. The OR operation can be mapped to the plus operation and the AND operation can be mapped to the multiply operation. One finds that when doing this, many mathematical rules correlate nicely. That is why it was done. Rules like associative and communicative make sense. It wasn't just wild insane mad men. When one understands the reasoning fully, one can except the choices made. It is just that in your schooling, you were never exposed to much Boolean algebra. That is too bad because so much of what we do with computers requires a level of understanding of how it works. Dwight