There are many different books in the ' crazy silly school ' series. If you have read 34 of the books and are yet to read 19 books How many books are there in the ' crazy silly school ' series?
There are many different books in the ' crazy silly school ' series. 

This means that the series consists of multiple books. 

If you have read 34 of the books and are yet to read 19 books, this means that you have read a total of 53 books. 

Therefore, the ' crazy silly school ' series consists of at least 53 books.