A section of road is 320 meters long. It has been repaired for 8 days. A meter is repaired every day. How many meters are left to be repaired?
一段公路长320米，已经修了8天，每天修a米，还剩多少米没修．
<gadget id="calculator">320 - 8</gadget>
<output>312</output>

<result>312</result>