The road construction team builds a 10-kilometer road. The full length (1/5) was repaired on the first day, and the full length (1/4) was repaired on the second day. How many kilometers are left to be repaired?
筑路队修一条10千米的公路．第一天修了全长的(1/5)，第二天修了全长的(1/4)，还有多少千米没有修？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">10 * (11/20)</gadget>
<output>11/2 = around 5.5</output>

<result>11/2 = around 5.5</result>