There is a shelf of literature books in the reading room of the school. After lending out 75% of the total number, another 80 books are placed. At this time, the books on the bookshelf are (1/3) of the original total number. How many literature books are on the shelf now?
学校阅览室内有一架文学书，借出总数的75%之后，又放上80本，这时书架上的书是原来总数的(1/3)．现在书架上放着多少本文学书？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">80 / (1/12)</gadget>
<output>960</output>

<gadget id="calculator">960 * (1/3)</gadget>
<output>320</output>

<result>320</result>