The fifth-grade book corner originally had 240 books, and 60 books were purchased this semester, an increase of what percentage?
五年级图书角原有图书240本，这学期又购进60本，增加了百分之几？
<gadget id="calculator">60 / 240</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>