This is the 15799th most frequent Russian word.
проданных
"Проданных" means "sold" (genitive plural or masculine/neuter genitive singular form).
Here, 'проданных' is used as an adjective, formed from the verb 'продать', describing the noun 'books'.
Количество проданных книг увеличилось.
The number of sold books increased.
In this sentence, 'проданных' serves as an attributive adjective modifying 'goods', providing additional information.
Мы обсудили детали проданных товаров.
We discussed the details of sold goods.
'Проданных' is used adjectivally to describe the noun 'shares', indicating the completion of their sale.