Uncle workers want to build a 25-kilometer road. Repair 3 kilometers every day, after 6 days of repairing, how many kilometers are left unrepaired?
工人叔叔要修一条25千米长的公路．每天修3千米，修了6天后，还有多少千米没有修？
<gadget id="calculator">3 * 6</gadget>
<output>18</output>

<gadget id="calculator">25 - 18</gadget>
<output>7</output>

<result>7</result>