In any case where (1) any school district is abolished and its land reverts to or becomes a part of two or more school districts, or (2) any land heretofore annexed to one school district is made a part of the district in which it is located, or (3) a new district is made by the creation of a new city, borough, township, or independent school district, out of one or more school districts, or (4) the boundary lines of any district are changed by the changing of the boundary lines of any city, incorporated town, borough, township, or school district, or (5) any part of any school district is merged with any other district or districts or parts thereof, then, in any such case, the school districts to which land has been annexed or from which land has been taken, or which have been newly created, shall make a just and proper adjustment and apportionment of all school property, real and personal, including funds, as well as indebtedness, and rental obligations to an approved school building authority, if any, to and among such school districts. Such adjustment and apportionment shall be made as of the date of the decree or order creating such new city, borough, township, or school district, or of the decree of the court or vote of the electors effecting such annexation or merger, or the first Monday of July following approval by the Council of Basic Education of the annexation for school purposes.