Today, computer companies sell many different programs for computers. First, there are programs for doing math problems. Second, there are programs for scientific studies. Third, some programs, called word processors, are like fancy typewriters. They are often used by writers and business people. Other programs, called CD-ROMs, are on compact discs (CDs). These programs have movies, book, and even music on the them. Finally, there are programs for fun. These include exciting games and puzzles for children and adults.