A rope is 40 meters long, (2/5) is used for the first time, and the remaining (1/3) is used for the second time. How long is this rope?
一根绳子长40米，第一次用去(2/5)，第二次用去剩下的(1/3)．这根绳子还有多长？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 * (2/5)</gadget>
<output>16</output>

<gadget id="calculator">40 - 16</gadget>
<output>24</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">24 * (1/3)</gadget>
<output>8</output>

<gadget id="calculator">40 - 16 - 8</gadget>
<output>16</output>

<result>16</result>