There is a section of road that has been repaired (4/7), and the unrepaired road is much less than the repaired one
有一段路，已修(4/7)，未修的比已修的少多少
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">1 - (4/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(4/7) - (3/7)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/7) / (4/7)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>