An order of ray-finned fish, also called the Microcyprini, and comprising mostly small, fresh-water fish. They are closely related to the Atheriniformes[?] and are occasionally included with them. Many popular aquarium fish, such as killifish and live-bearers, belong here.
... \sqrt {b^2-4ac}</math>
in the formula should be understood as "either of those element(s) of the field whose square equals b2 - 4ac". In some fields, som ...