There are 500 books in the library, 80 books are borrowed for the first time, 200 books are loaned out for the second time, and 40 books are returned, how many new books are there in the library at this time?
图书馆有500本图书，第一次借出80本，第二次借出200本，还回40本，这时图书馆存有新书多少本．
<gadget id="calculator">200 - 40</gadget>
<output>160</output>

<gadget id="calculator">80 + 160</gadget>
<output>240</output>

<gadget id="calculator">500 - 240</gadget>
<output>260</output>

<result>260</result>