[and] + [or] -- multiplication is primary
In mathematics, “xy”, means “x times y”. Multiplication is the default operation. This is odd, since multiplication is not as fundamental as addition. The mind skips over the rudiments in favor of a more advanced concept.
Multiplication is akin to “and”, and addition is the equivalent of “or”. On purely logical grounds, it is difficult to decide which is primary. But our algebraic notation suggests that there may be something special about “and”.