> 12 PM = noon is something I remember learning in kindergarden, and should be common knowledge for most adults in the US.
Well, maybe, although assuming a commonality between others' education and mine is always dangerous; but I've got way more respect for someone who understands a concept but doesn't know about an arbitrary exception to it, than for someone who understands a pile of arbitrary rules and doesn't know how to fit them to any conceptual framework.
12 PM = noon is something I remember learning in kindergarden, and should be common knowledge for most adults in the US.