For a section of road, the full length (1/9) was repaired on the first day, and the rest (1/4) was repaired on the second day. How much of the total length was repaired in two days.
一段路，第一天修了全长的(1/9)，第二天修了余下的(1/4)，两天共修了全长的多少．
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 - (1/9)</gadget>
<output>8/9 = around 0.888889</output>

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

<gadget id="calculator">(8/9) * (1/4)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(2/9) + (1/9)</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>