The green ribbon is shorter than the red ribbon (2/7), how much longer is the red ribbon than the green ribbon
绿彩带比红彩带短(2/7)，红彩带比绿彩带长多少
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">1 - (5/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(2/7) / (5/7)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>