A certain engineering team builds a road. On the first day, it repairs the full length (2/5), on the second day it repairs the remaining part (5/9) and 20 meters, on the third day it repairs the first day (1/ 4) Another 30 meters, so just finished repairing, how many meters is the total length of this section of road?
某工程队修筑一条公路，第一天修了全长的(2/5)，第二天修了剩下部分的(5/9)又20米，第三天修的是第一天的(1/4)又30米，这样正好修完，这段公路全长多少米？
<gadget id="calculator">20 + 30</gadget>
<output>50</output>

<gadget id="calculator">2 / 5</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">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(3/5) * (5/9)</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">(2/5) * (1/4)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (2/5) - (1/3) - (1/10)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">50 / (1/6)</gadget>
<output>300</output>

<result>300</result>