A rope is (4/5) meters long, (1/2) is used for the first time, (1/2) is used for the second time, how many meters is used for the second time.
一根绳子长(4/5)米，第一次用去它的(1/2)，第二次用去第一次的(1/2)，第二次用去多少米．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">(4/5) * (1/2) * (1/2)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>