The master and the 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). Then how many parts are processed by the master.
师徒俩人加工同样多的零件，当师傅完成(1/2)时，徒弟完成120个．当师傅完成任务时，徒弟完成(4/5)．则师傅加工零件多少个．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

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

<result>300</result>