A plastic rope is cut off by 2 decimeters and then connected to 6 decimeters, which is longer than the original total length (2/5). What is the original total length of this plastic rope?
一根塑料绳剪去2分米后又接上6分米，这时比原来的全长多了(2/5)，这根塑料绳原来全长多少分米．
<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">4 / (2/5)</gadget>
<output>10</output>

<result>10</result>