two-meter-long bamboo pole is inserted into a pond, 50% of which is above the water, and 25% is inserted into the mud. The pond is several meters deep.
一根两米长的竹竿插入一池塘中，50%露出水面，25%被插入泥中．这池塘水深几米．
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2 * (1/4)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>