It takes 4 days to build a road to repair the full length (2/5), so calculate how much it will cost to repair the full length (1/4).
修一条路4天修全长的(2/5)，照这样计算修全长的(1/4)用多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / 4</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/4) / (1/10)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>