There are a total of 145 books on the first and second shelves, 5 times more than the books on the third shelf. How many books are there on the third shelf?
第一层和第二层书架上共放了145本书，比第三层书架上的书的5倍还多5本，第三层书架上有多少本书？
<gadget id="calculator">145 - 5</gadget>
<output>140</output>

<gadget id="calculator">140 / 5</gadget>
<output>28</output>

<result>28</result>