Calculating Total Number of Books

At a bookstore, a set of books is organized into 3 shelves. Each shelf has 9 books. If the bookstore adds 4 more books to each shelf, how many books are there in total?

To solve this problem, first calculate the total number of books before the additional books are added by multiplying the number of shelves by the number of books per shelf. Then, find the total number of additional books, and add them to the initial total.