To build a canal, the full length (1/4) was built on the first day, but the second day was 7 meters shorter than the full length (2/5), and there were still 35 meters left to be repaired. How long is this canal in meters?
修一条水渠，第一天修了全长的(1/4)，第二天修的比全长的(2/5)少7米，还有35米没修，这条水渠长多少米？
<gadget id="calculator">35 - 7</gadget>
<output>28</output>

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

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">28 / (7/20)</gadget>
<output>80</output>

<result>80</result>