404. That’s an error.
The requested URL /bookmarks/mark?op=edit&bkmk=https://astarmathsandphysics.com/index.php?option=com_content&view=article&id=2052:de-morgan-s-laws&catid=160&Itemid=1799&title=de+Morgan%27s+Laws
was not found on this server. That’s all we know.