20% of a rope is used for the first time, and the remaining 20% is used for the second time, and the difference between the two times is 2 meters. What is the original length of this rope?
一根绳子第一次用去20%，第二次又用去余下的20%，两次相差2米．这根绳原来的长是多少米？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * (1/5)</gadget>
<output>4/25 = around 0.16</output>

<gadget id="calculator">(1/5) - (4/25)</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">2 / (1/25)</gadget>
<output>50</output>

<result>50</result>