A steel mill used 84,000 kWh of electricity in April, which was (1/7) less in May than in April. How many kilowatt-hours were saved in May compared to April?
一个炼钢厂，四月份用电84000千瓦时，五月份比四月份节约了(1/7)．五月份比四月份节约了多少千瓦时？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">84_000 * (1/7)</gadget>
<output>12_000</output>

<result>12_000</result>