There are two steel pipes of the same length, the first one is used first (1/5), then (2/3), the second one is used first (2/5), then (3/7), Which steel pipe is the longest remaining? How long is it?
有两根同样长的钢管，第一根先用去(1/5)，再用去(2/3)，第二根先用去(2/5)，再用去(3/7)，哪一根钢管剩下的长？长几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

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

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (1/5) - (2/3)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">1 - (2/5) - (3/7) - (2/15)</gadget>
<output>4/105 = around 0.038095</output>

<result>4/105 = around 0.038095</result>