certain workshop needs to produce a batch of 900 TV parts. Team A will do it alone in 12 days, and team B will do it in 18 days alone. First, team A will do it in 7 days. The remaining two groups will cooperate to finish it in a few days. ?
某车间要生产一批电视机零件900个，由甲组单独做12天完成，由乙组单独做18天完成，先由甲组做7天，剩下的两组合作，还要几天完成？
<gadget id="calculator">7 / 12</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 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(1/12) + (1/18)</gadget>
<output>5/36 = around 0.138889</output>

<gadget id="calculator">(5/12) / (5/36)</gadget>
<output>3</output>

<result>3</result>