The school bought 480 books and placed them on 5 bookshelves. Each shelf has 4 floors. How many books are placed on each floor on average?
学校买来480本书，放在5个书架上，每个书架有4层，平均每层放了多少本书？
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">480 / 20</gadget>
<output>24</output>

<result>24</result>