A batch of parts is processed, 60 parts are processed per hour, and after 5 hours exactly (2/5) of the total number of parts are left unfinished, how many parts are there in total in this batch?
加工一批零件，每小时加工60个，5小时后正好还剩下零件总数的(2/5)没有完工，这批零件共有多少个？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">5 / (3/5)</gadget>
<output>25/3 = around 8.333333</output>

<gadget id="calculator">60 * (25/3)</gadget>
<output>500</output>

<result>500</result>