poultry farm raises 6,400 poultry. Chickens account for 2/5 of the poultry, and chickens account for 8/5 of the ducks. How many ducks are raised?
一个家禽饲养场，饲养家禽6400只，鸡占家禽的(2/5)，鸡是鸭的(8/5)，养鸭多少只？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">8 / 5</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">(2/5) / (8/5)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">6_400 * (1/4)</gadget>
<output>1_600</output>

<result>1_600</result>