For a highway, the full length (1/4) was repaired on the first day, and the first day (4/5) was repaired on the second day. How much of the full length was repaired on the second day.
一条公路，第一天修了全长的(1/4)，第二天修的是第一天的(4/5)，第二天修了全长的多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/4) * (4/5)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>