Master Li processes 84 parts per hour, and Master Zhang processes 312 parts in 4 hours. How many more parts does Master Li process per hour than Master Zhang?
李师傅每小时加工零件84个，张师傅4小时加工零件312个．李师傅比张师傅每小时多加工零件几个？
<gadget id="calculator">312 / 4</gadget>
<output>78</output>

<gadget id="calculator">84 - 78</gadget>
<output>6</output>

<result>6</result>