Master Wang has to process 360 parts, and 20% of them have been processed in the first 4 days. According to this calculation, how many days will it take to process this batch of parts?
王师傅要加工360个零件，前4天已经加工了20%，照这样计算，加工完这批零件共需多少天？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / (1/5)</gadget>
<output>5</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>