The garment factory plans to produce 5,000 shirts a month, but it is completed in the first half of the month (3/5). If the second half of the month is as many as the first half, how many pieces have been overproduced this month?
服装厂计划一个月生产衬衫5000件，结果上半月完成(3/5)，如果下半月完成的与上半月同样多，这个月超额生产了多少件？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

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

<gadget id="calculator">(3/5) + (-2/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5_000 * (1/5)</gadget>
<output>1_000</output>

<result>1_000</result>