Cut off (4/5) of a rope, it is exactly (1/5) meter, how many meters is the original length of the rope?
一根绳子剪去它的(4/5)，正好是(1/5)米，这跟绳子原来长多少米．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/5) / (4/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>