A rope is 20 meters long, (2/5) of it is used for the first time, and (2/5) of it is used for the second time, how many meters are left?
一根绳子长20米，第一次用去它的(2/5)，第二次用去(2/5)米，还剩多少米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 * (2/5)</gadget>
<output>8</output>

<gadget id="calculator">20 - 8 - (2/5)</gadget>
<output>58/5 = around 11.6</output>

<result>58/5 = around 11.6</result>