Master Zhang and Master Li cooperate to produce a batch of the same parts. Master Zhang produces 18 per hour, and Master Li produces 12 per hour. When the task is completed, Master Zhang produces 108 parts. How many parts are there in this batch?
张师傅和李师傅合作生产一批同样的零件，张师傅每小时生产18个，李师傅每小时生产12个，当完成任务时张师傅生产了108个零件，这批零件共有多少个？
<gadget id="calculator">108 / 18</gadget>
<output>6</output>

<gadget id="calculator">18 + 12</gadget>
<output>30</output>

<gadget id="calculator">6 * 30</gadget>
<output>180</output>

<result>180</result>