A piece of wood is 8 meters long, if (1/4) is used up, ((())/(())) is left, how many meters are left.
一根木头长8米，用去(1/4)，还剩((())/(()))，还剩多少米．
<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">8 * (3/4)</gadget>
<output>6</output>

<result>6</result>