There are 320 science books and story books in the school library, and the number of story books is three times that of science books. How many story books are there?
学校图书馆有科技书和故事书共320本，其中故事书的本数是科技书的3倍，故事书有多少本？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">320 / 4</gadget>
<output>80</output>

<gadget id="calculator">320 - 80</gadget>
<output>240</output>

<result>240</result>