This is not a counting book, but an adding book; Duke (Archaeologists Dig for Clues, 1997, etc.) uses number-driven events to introduce simple addition, thereby reinforcing the learning of numbers, and in the process creating an interesting story that shows off the personality of each character. ``One lonely guinea pig plus one other lonely guinea pig make two smiling guinea pigs.'' As the animals increase in number, they become a gang, picnicking, jumping, singing till they meet up with ``ten mom or dad guinea pigs,'' and make twenty--or plenty. A lot of clear space and Duke's unpretentious, almost cartoonish illustrative style has to its credit many details that make the book even more fun: a homemade costume constructed of feathers and paper clips; a boom box, a vending machine, and other paraphernalia that children will like. The numerals appear as big as life in the middle of the scenes, in a book that is warm and playful from beginning to end. (Picture book. 3-7)
