When Xiao Ming reads a book, he reads an average of 13 pages a day, and reads exactly half of the book in 24 days. How many pages does this book have?
小明看一本书，平均每天看13页，24天正好看了这本书的一半，这本书一共有多少页？
<gadget id="calculator">13 * 24 * 2</gadget>
<output>624</output>

<result>624</result>