Worker Master Wang finished the whole batch of parts in two days. On the first day, 60% of the parts were processed, and 7 boxes were packed with 20 pieces. The parts processed on the second day were packed into 5 boxes. How many parts are there in this batch?
工人王师傅用两天时间加工完成整批零件，第一天加工了60%，装了7盒余20个，第二天加工的零件正好装了5盒，这批零件有多少个？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">5 / (2/5)</gadget>
<output>25/2 = around 12.5</output>

<gadget id="calculator">(25/2) - 7 - 5</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 / (1/2)</gadget>
<output>40</output>

<gadget id="calculator">40 * (25/2)</gadget>
<output>500</output>

<result>500</result>