There are three nylon ropes, the first is (2/5) meter long, the second is (1/3) meter longer than the first, the third is (1/6) meter shorter than the second, and the third is longer How much rice?
有三根尼龙绳，第一根长(2/5)米，第二根比第一根长(1/3)米，第三根比第二根短(1/6)米，第三根长多少米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/3) - (1/6)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/5) + (1/6)</gadget>
<output>17/30 = around 0.566667</output>

<result>17/30 = around 0.566667</result>