A canal was built in a certain township. The first phase of the project completed 50% of the total length, and the second phase of the project completed 35% of the total length. There is still 180 meters left to be repaired. How long is this canal around the mountain?
某乡修一条水渠，第一期工程修了全长的50%，第二期工程修了全长的35%，还剩180米没有修，这条环山水渠长多少米？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">35 / 100</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">1 - (1/2) - (7/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">180 / (3/20)</gadget>
<output>1_200</output>

<result>1_200</result>