The school library buys 200 books and put them on two 4-story bookshelves. On average, how many books should be placed on each floor?
学校图书室买来200本书，要放在2个4层的书架上，平均每层要放几本？
<gadget id="calculator">200 / 2 / 4</gadget>
<output>25</output>

<result>25</result>