There is a project that Team A needs to complete in 15 days and Team B in 18 days. After the two teams cooperate for 6 days, Team A will do the rest alone. How many days will it take to complete?
有一项工程，甲队要15天完成，乙队要18天完成，两队合作6天后，剩下的由甲队独做，还要几天完成？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

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

<gadget id="calculator">(1/15) + (1/18)</gadget>
<output>11/90 = around 0.122222</output>

<gadget id="calculator">(11/90) * 6</gadget>
<output>11/15 = around 0.733333</output>

<gadget id="calculator">1 - (11/15)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">(4/15) / (1/15)</gadget>
<output>4</output>

<result>4</result>