The teacher corrected 66 compositions, 12 of which have already been corrected. If 9 are corrected every 2 hours, how many hours will it take to complete the correction?
老师批改66篇作文，已对批改了12篇，如果每2时批改9篇，还要几小时能批改完？
<gadget id="calculator">66 - 12</gadget>
<output>54</output>

<gadget id="calculator">54 / 9</gadget>
<output>6</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<result>12</result>