A highly original and entertaining math concept book invites children to puzzle out Roman numerals by counting pigs in detailed barnyard and playground scenes. The concise text explains the mechanics of how just seven letters can be used in various combinations to stand for any number from 1 to 1000 or more, as the pigs demonstrate every step of the way. After the brief explanation, readers can test their understanding of, say, XIX by counting the 19 trees in an outdoor scene in which pigs predominate. Geisert is a meticulous draftsman whose etchings provide the perfect medium for his message. Although there is a lot to look at and count on every page, the drawings never seem busy or redundant, even in the case of a double-page-spread illustration that shows MM pigs. Throughout, Geisert's wry humor sets the tone as his 2000 pigs explore the landscape of their rural American home. (Ages 4-9)