Uncle Li works from 8:00 in the morning to 11:00 in the morning, and from 2:00 in the afternoon to 5:00 in the afternoon to make a total of 72 parts. How many parts does Uncle Li make on average per hour?
李叔叔每天早上8：00工作到11：00，下午2：00工作到下午5：00共做72个零件，李叔叔平均每小时要做几个零件？
<gadget id="calculator">3 + 3</gadget>
<output>6</output>

<gadget id="calculator">72 / 6</gadget>
<output>12</output>

<result>12</result>