For the purposes of computing allowances and apportionments from the State School Fund for the advance apportionment, first principal apportionment, and second principal apportionment on the basis of average daily attendance:
(a)
Each elementary school district shall be deemed to comprise the kindergartens and grades 1 to 8, inclusive, maintained by the district, and the seventh and eighth grades of the district not maintained by the district because of the attendance upon a junior high school of pupils who would otherwise attend upon seventh and eighth grades maintained by the district.
(b)
Each high school district shall be deemed to comprise all of grades 9 to 12, inclusive, maintained within the high school district whether maintained by a high school district.
(c)
Each unified school district shall be deemed to be an elementary school district comprising the kindergartens and grades 1 to 8, inclusive, maintained by the district and the seventh and eighth grades of the district not maintained by the district in elementary schools because of the attendance upon a junior high school of pupils who would otherwise attend the seventh and eighth grades maintained in elementary schools by the district, and a high school district comprising all of grades 9 to 12, inclusive.