The school library has 50 bookshelves, each shelf has 3 floors, and each floor contains 50 books. How many books are there in the school library?
学校图书馆有50个书架，每个书架3层，每层放书50本，学校图书馆一共有图书多少本
<gadget id="calculator">50 * 3 * 50</gadget>
<output>7_500</output>

<result>7_500</result>