A steel pipe is 0.8 meters long, if (3/5) meters are used up, how many meters are left?
一根钢管长0.8米，用去(3/5)米，还剩多少米．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">0.8 - (3/5)</gadget>
<output>0.2</output>

<result>0.2</result>