The factory used 720 tons of coal in October, saving (1/4) compared with September. How many tons were saved?
工厂十月份用煤720吨，比九月份节约了(1/4)，节约了多少吨？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">720 / (3/4)</gadget>
<output>960</output>

<gadget id="calculator">960 - 720</gadget>
<output>240</output>

<result>240</result>