Two engineering teams jointly excavated a 117-meter-long tunnel. The construction is opposite to each other from one end, and it takes 13 days to get through. Team A excavates 4 meters per day, how many meters does Team B excavate per day?
两个工程队共同开凿一条117米长的隧道．各从一端相向施工，13天打通．甲队每天开凿4米，乙队每天开凿多少米？
<gadget id="calculator">117 / 13</gadget>
<output>9</output>

<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<result>5</result>