A factory used 5,400 tons of water in October, saving 20% compared to September. How many kilograms of water was used in September?
某工厂十月份用水5400吨，比九月份节约20%，九月份用水多少千克？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5_400 / (4/5)</gadget>
<output>6_750</output>

<gadget id="calculator">6_750 * 1_000</gadget>
<output>6_750_000</output>

<result>6_750_000</result>