If A and B cooperate to complete a project in 18 days, and A, B, and C cooperate in 12 days, how many days will it take for C to complete it alone?
一项工程，甲、乙合作18天完成，甲、乙、丙合作12天也可以完成，丙单独做需要多少天完成？
<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>1/36 = around 0.027778</output>

<gadget id="calculator">1 / (1/36)</gadget>
<output>36</output>

<result>36</result>