A glass of fruit juice has already been drunk (1/3), and what is drunk is the rest ((())/(())).
一杯果汁，已经喝掉(1/3)，喝掉的是剩下的((())/(()))．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/3) / (2/3)</gadget>
<output>1/2 = around 0.5</output>

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