40% of the total length of a road has been built, and 180 meters remain to be repaired. What is the total length of this road in meters?
修一条公路，修了全长的40%，还剩180米没有修，这条公路共长多少米．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">180 / (3/5)</gadget>
<output>300</output>

<result>300</result>