To build a road, team A completed it alone in 15 days, and team B completed it in 12 days. After the two teams jointly repaired it in 4 days, B was transferred away, and team B continued to complete the rest. How many days did Team B practice?
修一条公路，甲队独修15天完成，乙队独修12天完成，两队合修4天后乙调走，剩下的路由乙队继续修完．乙队共修了多少天．
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/15) + (1/12)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(3/20) * 4</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / (1/12)</gadget>
<output>24/5 = around 4.8</output>

<gadget id="calculator">(24/5) + 4</gadget>
<output>44/5 = around 8.8</output>

<result>44/5 = around 8.8</result>