There is a wire, cut off its (21/50) for the first time, cut off the first (5/7) for the second time, and the rest is 2 meters less than the first cut, this wire was originally How many meters is it?
有一根电线，第一次剪去它的(21/50)，第二次剪去第一次的(5/7)，剩下的比第一次剪去的少2米，这根电线原来是多少米？
<gadget id="calculator">21 / 50</gadget>
<output>21/50 = around 0.42</output>

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

<gadget id="calculator">(21/50) * (5/7)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (21/50) - (3/10)</gadget>
<output>7/25 = around 0.28</output>

<gadget id="calculator">(21/50) - (7/25)</gadget>
<output>7/50 = around 0.14</output>

<gadget id="calculator">2 / (7/50)</gadget>
<output>100/7 = around 14.285714</output>

<result>100/7 = around 14.285714</result>