A 400-meter-long road was built. On the first day, the full-length (1/4) was built, and on the second day, the full-length (1/5) was built. How many meters were built in total in these two days? (Only the comprehensive formula is listed, no calculation is required)
修一段长400米的路，第一天修了全长的(1/4)，第二天修了全长的(1/5)，这两天一共修了多少米？(只列综合式，不用计算)
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">400 * (9/20)</gadget>
<output>180</output>

<result>180</result>