The school library has purchased a batch of books, including 602 story books, which are more than popular science books (2/5). How many popular science books have the library purchased?
学校图书馆购买了一批图书，其中故事书有602本，比科普类读物多(2/5)，图书馆购买了多少本科普类读物？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">602 / (7/5)</gadget>
<output>430</output>

<result>430</result>