Hongxing Primary School used 480 kWh of electricity in October, saving (1/9) compared to September. How many kWh of electricity was used in September?
红星小学十月份用电480千瓦时，比九月份节约了(1/9)，九月份用电多少千瓦时？
<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">480 / (8/9)</gadget>
<output>540</output>

<result>540</result>