The school used 3600 kWh of electricity in the first half of October, and saved (1/5) the second half of the month compared with the first half. How much kWh was used in the second half of the month?
学校10月份上半月用电3600千瓦时，下半月比上半月节约(1/5)，下半月用电多少千瓦时？
<gadget id="calculator">1 / 5</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">3_600 * (4/5)</gadget>
<output>2_880</output>

<result>2_880</result>