The master and the apprentice jointly produce a batch of parts, the master produces 28 per hour, the apprentice produces 22 per hour, and the two work together for 5 hours to complete the task. How many parts are there in this batch?
师徒俩共同生产一批零件，师傅每小时生产28个，徒弟每小时生产22个，两人共同生产5小时完成任务．这批零件共有多少个？
<gadget id="calculator">28 + 22</gadget>
<output>50</output>

<gadget id="calculator">50 * 5</gadget>
<output>250</output>

<result>250</result>