There is a shelf of story books in the school library. After lending out (3/4) of the total number, another 60 books are put on the shelf. At this time, the number of books on the shelf is (1/3) of the original total number. Find out how many books are on the shelf right now.
学校图书室内有一架故事书，借出总数的(3/4)之后，又放上60本，这时架上的书是原来总数的(1/3)．求现在书架上放着多少本书．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3 / 4</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">60 / (1/12)</gadget>
<output>720</output>

<gadget id="calculator">720 * (1/3)</gadget>
<output>240</output>

<result>240</result>