Simplify the following text for a Grade 11 native English-speaking person.
Original: The smaller republic of Montenegro severed its economy from federal control and from Serbia during the MiloÅ eviÄ era . During the Serbia and Montenegro period , both republics had separate central banks , different currencies - Montenegro first used the Deutsche Mark , then the euro when it replaced the Deutsch Mark , while Serbia used the Serbian dinar as official currency .
Simplified: Serbia and Montenegro worked together in only some political areas .