To build a section of road, the full length (3/10) was built on the first day, and 120 meters was repaired on the second day, leaving the full length (2/5). How long is this road in meters?
修一段路，第一天修了全长的(3/10)，第二天修了120米，还剩下全长的(2/5)．这段路全长多少米？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

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

<gadget id="calculator">1 - (3/10) - (2/5)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">120 / (3/10)</gadget>
<output>400</output>

<result>400</result>