For a road, the ratio of repaired to unrepaired is 5:4, how much of the total length has been repaired (fraction).
一条公路，已修的和未修的比是5：4，已修了全长的多少(分数)．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<result>5/9 = around 0.555556</result>