There are 1,500 books in the school library, an increase of 300 books. By what percentage?
学校图书室现有图书1500册，比原来增加了300册．增加了百分之几？
<gadget id="calculator">1_500 - 300</gadget>
<output>1_200</output>

<gadget id="calculator">300 / 1_200</gadget>
<output>1/4 = around 0.25</output>

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