The price of a commodity is reduced by (1/5) during the promotion period, and then increased by (1/5) after the promotion. At this time, the price of the commodity is the original price ((())/(())).
某商品在促销时期降价(1/5)，促销过后又涨(1/5)，这时商品的价格是原来价格的((())/(()))．
<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">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) / 1</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(4/5) * (6/5)</gadget>
<output>24/25 = around 0.96</output>

<result>24/25 = around 0.96</result>