Simplify the following text for a Grade 7 native English-speaking person.
Original: He is currently heard on Premiere Radio Networks ' weekly syndicated radio programs based on the American Top 40 franchise : Casey Kasem 's American Top 40 : The '70s and Casey Kasem 's American Top 40 : The '80s are replays of AT40 shows from the respective decades . He also hosted American Top 20 and American Top 10 .
Simplified: Kasem is the host of two weekly radio shows , American Top 20 with Casey Kasem and American Top 10 with Casey Kasem .