The National Symphony Orchestra's Exxon/Arts Endowment Conductor, Hugh Wolff, had an inspired idea for this week's children's and family concerts. He decided to put on a complete staged version of Maurice Ravel's one-act opera, "The Mischievous Child."

While that is not a literal translation of "L'enfant et les sortileges," it is certainly a correct picture of the behavior of the boy who is the central figure in Ravel's betwitching music drama. He is a bad boy who throws a tantrum and gets into lots of trouble because of it.

At the final concert yesterday, the Kennedy Center Concert Hall was transformed. With the orchestra concealed behind a decorated screen, the stage became a world filled with a pair of animated arm chairs, an angry grandfather clock, talking wallpaper, a waltzing teapot and cup, an arithmetic teacher who thinks 2 and 2 are 18, fire that torments the boy, a tree on which he once carved his initials, and a zooey collection of owls, bats, cats that sing a duet, frogs and a squirrel. There is a loving shepherd and shepherdess and, inescapably, the bad boy's mother.

Acting as his own narrator, Wolf did a super job of keeping the young audience in close touch with all that was going on, which was not too hard since it all began when the boy came home from school and decided that instead of doing his homework he was going to be "bad, bad, bad!" Wolff also proved an excellent conductor of the subtle music.

Bob Brown's puppets were there to move the characters around as they came to life, and the chorus from George Marshall High School, singing from behind the orchestra, had no trouble with Ravel's enchanting score.

The soloists were Dorothy Kingston, Ellen Lang, Beth Rothenberg, Dana Krueger, Stanley Cornett, and Ben Holt. With the orchestra, which played Ravel with a luscious sound, they gave their youthful listeners a grand introduction to one of opera's most alluring works.