The cafeteria burns 5 tons of coal in September and 4.5 tons of coal in October. How much is the savings?
食堂九月份烧煤5吨，十月份烧煤4.5吨，节约了百分之几？
<gadget id="calculator">5 - 4.5</gadget>
<output>0.5</output>

<gadget id="calculator">0.5 / 5</gadget>
<output>0.1</output>

<result>0.1</result>