The number of parts processed by the master and the apprentice is the same. When the master processes half, the apprentice only processes 120 parts. When the master completes, the apprentice completes (4/5). How many parts are there in this batch?
师徒加工零件的数量相同，师傅加工一半时，徒弟只加工120个，师傅完成时，徒弟完成(4/5)．问这批零件共有多少个？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) / 2</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">120 / (2/5)</gadget>
<output>300</output>

<result>300</result>