Someone bought a stock at the beginning of the year, and the stock fell by 50% in the middle of the year, so how much should it rise by the end of the year to maintain its original value.
有人在年初买了一种股票，该股票年中下跌50%，那么到年底应该上涨多少才能保持原值．
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 * (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) / (1/2)</gadget>
<output>1</output>

<result>1</result>