The garment factory plans to produce a batch of children's clothing. On the first day, it produced 30% of the total clothing, and on the second day it produced 9/20 of the total clothing. The second day produced 960 more pieces than the first day. How many pieces of children's clothing are there?
服装厂计划生产一批童装，第一天生产了服装总量的30%，第二天生产了服装总量的(9/20)，第二天比第一天多生产了960件，这批童装一种有多少件？
<gadget id="calculator">9 / 20</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(9/20) - (3/10)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">960 / (3/20)</gadget>
<output>6_400</output>

<result>6_400</result>