A rope is 18 meters long. For the first time, 2/5 of the full length is used, and for the second time, 1/4 of the full length is used. How much less is the second time than the first time?
一根绳子长18米，第一次用去全长的(2/5)，第二次用去全长的(1/4)，第二次比第一次少用多少米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">18 * (2/5)</gadget>
<output>36/5 = around 7.2</output>

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

<gadget id="calculator">18 * (1/4)</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">(36/5) - (9/2)</gadget>
<output>27/10 = around 2.7</output>

<result>27/10 = around 2.7</result>