Master Zhang makes 18 parts per hour, and Master Wang makes 20 parts per hour. The two work at the same time and finish it in 6 hours. How many parts are there in this batch?
张师傅每小时做18个零件，王师傅每小时做20个零件，两人同时工作，6小时后完成，这批零件有多少个？
<gadget id="calculator">18 + 20</gadget>
<output>38</output>

<gadget id="calculator">38 * 6</gadget>
<output>228</output>

<result>228</result>