The phrase "doeth number" is an archaic way of saying "performs an action" or "does something." Some possible synonyms for this phrase include "carries out a task," "executes a plan," "accomplishes a goal," "undertakes a project," or "fulfills a duty." Other similar phrases might be "engages in an activity," "takes action," "completes a mission," "fulfills a responsibility," or "makes happen." Depending on the context and the specific type of action being taken, there could be many different ways to convey the idea of someone doing something in a clear and concise manner.