In the past, combining children of different ages in one classroom was usually a failure; it resulted in confused younger children, who were given inadequate attention and instruction, and bored older ones, who had to sit through previously learned lessons  Recently, however, the practice has been revived with excellent results
Mixed-age classrooms today are stimulating to older children and enable younger children to learn much more efficiently than in standard classrooms
Today's mixed-age classrooms, unlike those of the past, emphasize group projects that are engaging to students of different ages.