A project can be completed by team A alone in 15 days, and team B alone in 12 days. After 6 days of cooperation between teams A and B, what fraction of the project is left unfinished?
一项工程，甲队单独做15天完成，乙队单独做12天完成，甲、乙两队合作6天后，还剩下这项工程的几分之几没完成？
<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) * 6</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>