ONE BALLERINA TWO

A sleek, graceful girl of perhaps 12, neatly clad in a leotard, and a disheveled preschooler wearing a baggy sweater and legwarmers take turns demonstrating some familiar moves: ten careful pliÇs, nine approximate knee bends, eight precise changements, seven oddly assorted little jumps, etc. The logical- minded may enjoy observing that, while the figures are repeated the appropriate number of times, the activities sometimes aren't- -e.g., the older girl is caught at six stages of a single pirouette. The illustrations are delightful and the implicit story is charming, especially when it's wrapped up with ``One happy hug.'' As quintessentially simple as Ormerod's own wonderfully expressive line. (Picture book. 3-8)