To build a canal, the full length (2/5) was built on the first day, and the full length (3/20) was repaired less than the first day on the second day. What fraction of the total length was repaired?
修一条水渠，第一天修了全长的(2/5)，第二天比第一天少修了全长的(3/20)，一共修了全长的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(2/5) - (3/20)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) + (2/5)</gadget>
<output>13/20 = around 0.65</output>

<result>13/20 = around 0.65</result>