Both master and apprentice process the same number of parts. When the master completes (1/2), the apprentice completes 120. When the master completes the task, the apprentice completes (4/5). How many parts are there in this batch?
师徒俩人加工同样多的零件．当师傅完成了(1/2)时，徒弟完成了120个．当师傅完成了任务时，徒弟完成了(4/5)，这批零件共有多少个？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/2) * (4/5)</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">300 * 2</gadget>
<output>600</output>

<result>600</result>