The factory used 720 tons of coal in October, saving (1/9) compared to September. How many tons were saved?
工厂十月份用煤720吨，比九月份节约了(1/9)，节约了多少吨？
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 - (1/9)</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">720 / (8/9)</gadget>
<output>810</output>

<gadget id="calculator">810 * (1/9)</gadget>
<output>90</output>

<result>90</result>