After using up (3/5) of a rope, there is still (3/5) meters left, what is the original length of the rope?
一根绳子用去了(3/5)后，还剩(3/5)米，这根绳子原长多少米．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/5) / (2/5)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>