The shoe factory produces leather shoes, and the ratio of the double number produced in October to September is 5:4. 2000 pairs will be produced in October, how many pairs will be produced in September?
鞋厂生产皮鞋，十月份生产双数与九月份的比是5：4．十月份生产2000双，九月份生产多少双？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2_000 * (4/5)</gadget>
<output>1_600</output>

<result>1_600</result>