The number of story books in the school library is more than that of science books (1/3). There are 640 story books, but how many science books are there?
学校图书室的故事书本数比科技书多(1/3)，故事书有640本，科技书有多少本？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 + (1/3)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">640 / (4/3)</gadget>
<output>480</output>

<result>480</result>