On a bookshelf, there are 46 books on the first floor, 70 books on the second and third floors, and 52 books on the fourth floor. How many books are on each floor on average?
一个书架上第一层放了46本书，第二层和第三层共放了70本书，第四层放了52本书，平均每层放了多少本书？
<gadget id="calculator">46 + 70 + 52</gadget>
<output>168</output>

<gadget id="calculator">168 / 4</gadget>
<output>42</output>

<result>42</result>