Process a batch of children's clothing, processing 6% of the total per day. After 8 days, due to the improvement of clothing technology, 20 more pieces are processed per day than before, and it takes another 8 days to complete all tasks. How many pieces of children's clothing are there in this batch?
加工一批童装，每天加工总数的6%，8天后，由于制衣技术的改进，每天比原来多加工20件，又用了8天完成全部任务．这批童装共有多少件？
<gadget id="calculator">6 / 100</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">(3/50) * 8</gadget>
<output>12/25 = around 0.48</output>

<gadget id="calculator">1 - (12/25)</gadget>
<output>13/25 = around 0.52</output>

<gadget id="calculator">(13/25) / 8</gadget>
<output>13/200 = around 0.065</output>

<gadget id="calculator">(13/200) - (3/50)</gadget>
<output>1/200 = around 0.005</output>

<gadget id="calculator">20 / (1/200)</gadget>
<output>4_000</output>

<result>4_000</result>