rope is 20 meters long, (1/4) is used for the first time, and (1/5) of the full length is used for the second time, how much less is used for the second time than the first time?
一根绳子长20米，第一次用去(1/4)，第二次用去全长的(1/5)，第二次比第一次少用多少米？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 * (1/4)</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 * (1/5)</gadget>
<output>4</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<result>1</result>