Master Wang processed a total of 320 parts from 8 am to 12 noon. How many parts does he process per hour on average.
王师傅从上午8时到中午12时，共加工320个零件，他平均每小时加工零件多少个．
<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">320 / 4</gadget>
<output>80</output>

<result>80</result>