A 2-meter-long wire, 25% of the total length is used for the first time, and (1/4) meter is used for the second time, how many meters are left.
一根2米长的电线，第一次用去全长的25%，第二次用去(1/4)米，剩下多少米．
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

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

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

<gadget id="calculator">2 - (1/2) - (1/4)</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>