Li Ming and Zhang Dong are running on the playground. Li Ming takes 4 minutes to run a lap, and Zhang Dong takes 5 minutes to run a lap. How much faster is Li Ming than Zhang Dong?
李明和张冬在操场上跑步，李明跑一圈用时4分钟，张冬跑一圈用时5分时，李明比张冬快多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) / (1/5)</gadget>
<output>1/4 = around 0.25</output>

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