A power plant used 2 tons of coal in August, saving 0.5 tons compared to July. How much was the saving?
一个发电厂8月份用煤2吨，比7月份节约0.5吨，节约了百分之几？
<gadget id="calculator">2 + 0.5</gadget>
<output>2.5</output>

<gadget id="calculator">0.5 / 2.5</gadget>
<output>0.2</output>

<result>0.2</result>