There are 5600 chickens in the farm, and the number of ducks is less than the number of chickens (3/7). How many ducks are there in the farm?
饲养场有鸡5600只，鸭子的只数比鸡的只数少(3/7)，饲养场养鸭多少只？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (3/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">5_600 * (4/7)</gadget>
<output>3_200</output>

<result>3_200</result>