The Great Divide

In this crafty story of a cross-country race called ""The Great Divide,"" numerical division accounts for the narrowing of the field. Eighty costumed competitors (in 10 groups of eight) begin the event on bicycles, but only half of them ford a rocky red canyon to continue: ""On with the race./ Head for a boat!/ Forty racers now have to float!"" These 40 (now 10 groups of four) climb aboard two big rowboats, and a whirlpool diminishes their number by half again. Dodds (Sing, Sophie!) continues reducing the group to 10 and to five, at which point ""one runner stops with a rock in her shoe,"" enabling the final four to grab tandem bikes. The author demonstrates rather than describes the math, and her terse rhymes reinforce the racers' sense of urgency. Meanwhile Mitchell's individualized portraits of the athletes raise the book's quotient of pleasure. The illustrator, making a notable picture-book debut, carefully includes the dwindling number of eight clowns, eight cowhands, eight flappers, eight pirates and so on in her well-organized acrylic paintings; aspiring number crunchers can count the participants with ease. Among the top contenders, likable characters emerge: a jailbird wears a determined grin, a grandmotherly lady rides a galloping horse and a firefighter sticks out her tongue in exhaustion. All lessons should be this gratifying. Ages 5-10. (Nov.)