A project that used to take 12 days to complete is now completed in only 9 days. How much is the working time reduced?
一项工程，原来要用12天完成，现在只用9天完成，工作时间减少了百分之几？
<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

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