The factory used 480 tons of coal in September, which was 25% less than that in August. How many tons were saved?
工厂九月份用煤480吨，比八月份节约了25%，节约了多少吨？
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">480 / (3/4)</gadget>
<output>640</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">640 * (1/4)</gadget>
<output>160</output>

<result>160</result>