 For example, the schools could have modular classrooms that can be opened up for larger group lectures, or partitioned for smaller group discussions; special-purpose rooms could be designed such that multiple usage of such rooms can be made possible; common areas such as corridors and study areas could be designed such that they can be expanded learning spaces.Launched in May 1999, PRIME was estimated to cost S$4.5 billion and is implemented in phases.As of September 2007, 243 schools have been included in the earlier nine phases of PRIME.