Jinxin Leather Shoes Factory plans to produce 3,600 pairs of leather shoes in September, but it completed the plan in the first half of the month (3/5), and in the second half of the month (5/8). How many pairs of leather shoes were overproduced in September?
金鑫皮鞋厂计划九月份生产皮鞋3600双，结果上半月完成了计划的(3/5)，下半月完成了计划的(5/8)．九月份超额生产了多少双皮鞋？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">3_600 * (3/5)</gadget>
<output>2_160</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">3_600 * (5/8)</gadget>
<output>2_250</output>

<gadget id="calculator">2_250 - 3_600</gadget>
<output>-1_350</output>

<gadget id="calculator">2_160 + (-1_350)</gadget>
<output>810</output>

<result>810</result>