On Mondays and Fridays in early May, nearly 18,000 children-the equivalent of all

On Mondays and Fridays in early May, nearly 18,000 children-the equivalent of all the elementary students in suburban Glencoe, Wilmette, Glenview, Kenilworth, Winnetka, Deerfield, Highland Park and Evanston-are assigned to classes with no teacher.