It has been 4 days to build a 5-kilometer road, and (4/5) kilometers are repaired every day, and the rest will be completed in 2 days. How many kilometers are repaired on average per day?
修一条5千米的公路，已经修了4天，每天修(4/5)千米，剩下的要2天修完，平均每天修多少千米？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * 4</gadget>
<output>16/5 = around 3.2</output>

<gadget id="calculator">5 - (16/5)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">(9/5) / 2</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>