There are two bookshelves, each with 4 floors, and there are 248 books in total. How many books are placed on each shelf on average?
有两个书架，每个书架4层，共放有248本书，平均每个书架每层放多少本？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">248 / 8</gadget>
<output>31</output>

<result>31</result>