Uncle workers repaired a road. They repaired the full length (2/7) on the first day and the full length (3/7) on the second day. What fraction of the road did they build in total? How much of this road is left unrepaired?
工人叔叔修一条公路，第一天修了全长的(2/7)，第二天修了全长的(3/7)，他们一共修了这条公路的几分之几？还剩下这条公路的几分之几没修？
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

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

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