Within this total pattern of elements selected to achieve the school's projected goals there is a second level-the scope of an area. Whether this be called a subject field, an interdiscipline or a domain, it is a subject within the total scope. What from the dis- cipline of mathematics is appropriate for an elementary school, for a secondary school?. The third level of scope determination concerns the individual teacher within the broad framework of the curriculum. What theorems shall the teacher of geometry include? ... The fourth level relates to an individual lesson.