The ratio of the cut length to the remaining length of a piece of iron wire is 2:5, and then 20 meters are cut off from the remaining length, then the ratio of the length cut twice to the remaining length is 4:5, how many meters is the length of the wire.
一根铁丝截去的和剩下的长度比是2：5，再从余下的截去20米，则两次截去的与余下的长度比是4：5，这根铁丝长多少米．
<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(5/7) - (5/9)</gadget>
<output>10/63 = around 0.15873</output>

<gadget id="calculator">20 / (10/63)</gadget>
<output>126</output>

<result>126</result>