A project can be completed by team A alone in 8 days and by team B in 12 days. Now, after two teams have done it at the same time for a few days, Team A will be transferred away, and the remaining team B will finish within 7 days. How many days did Team A do?
一项工程，甲队单独做要8天完成，乙队单独做要12天完成．现在两队同时做了几天后，甲队调走，余下的乙队在7天内完成．甲队做了几天？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 7</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">1 - (7/12)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) + (1/12)</gadget>
<output>5/24 = around 0.208333</output>

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

<result>2</result>