The children's clothing factory rushed to produce a batch of children's clothing, and has already produced 35% of the total. If it is just half of the task to produce 450 sets, how many sets of this batch of children's clothing are there?
童装厂赶制一批童装，已经生产了总数的35%，如果再生产450套正好完成了任务的一半，这批童装共有多少套？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">35 / 100</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">(1/2) - (7/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">450 / (3/20)</gadget>
<output>3_000</output>

<result>3_000</result>