To build a road, the full length (1/5) was built on the first day, and the full length (1/4) was built on the second day. A total of 1,800 meters was built in two days. How many meters is this road?
修一条路，第一天修了全长的(1/5)，第二天修了全长的(1/4)，两天一共修了1800米，这条路有多少米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) + (1/4)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1_800 / (9/20)</gadget>
<output>4_000</output>

<result>4_000</result>