A project is completed in 30 days by the cooperation of teams A and B. If the two teams cooperate for 12 days, what fraction of the project is left?
一项工程，甲、乙两队合作30天完成，若两队合作12天后，还剩下这项工程的几分之几？
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/30) * 12</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>