The electricity consumption of a shopping mall in October is less than that in September (1/5), and the electricity consumption in October is the same as in September.
某商场十月份的用电量比九月份少(1/5)，十月份的用电量是九月份的多少．
<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>

<result>4/5 = around 0.8</result>