A wire (4/5) meters, cut off (2/5), there is still ((())/(())); if cut off (2/5) meters, how many meters are left.
一根铁丝(4/5)米，截去(2/5)，还剩下((())/(()))；若截去(2/5)米，还剩下多少米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>