A rope cuts off the full length (1/4) for the first time, cuts off the remaining (2/3) for the second time, and cuts off the whole length for the second time.
一根绳子第一次截去全长的(1/4)，第二次截去余下的(2/3)，第二次截去全长的多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(3/4) * (2/3)</gadget>
<output>1/2 = around 0.5</output>

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