There are three types of books in the school library, among which literature books and popular science books account for (4/5) of the total number of books, and popular science books and reference books account for (3/5) of the total number of books. Do you know how many popular science books account for the total number of books?
学校图书馆有三类书，其中文学书和科普书共占图书总数的(4/5)，科普书和工具书共占用图书总数的(3/5)．你知道科普书占图书总数的几分之几？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(3/5) - (1/5)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>