40% of a 12-kilometer road has been built, how many kilometers have been built?
修一条长12千米的公路，已经修了40%，修了多少千米？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">12 * (2/5)</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>