To build a road, the ones that have been built are the ones that have not been repaired (5/7), so how much less is the one that has been repaired than the one that has not been repaired?
修一条公路，已修的是未修的(5/7)，那么已修的比未修的少多少？
<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">(7/12) - (5/12)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/6) / (7/12)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>