A highway is 15 kilometers long, 12 kilometers have been repaired, and how much is left to be repaired.
一条公路长15千米，已经修了12千米，还剩多少没有修．
<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<gadget id="calculator">3 / 15</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>