There are 400 chickens in the farm, and the number of roosters accounts for (1/20) of the total number of chickens. How many hens are there in the farm?
饲养场共有鸡400只，其中公鸡的只数占鸡的总数的(1/20)，饲养场有母鸡多少只？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">400 * (1/20)</gadget>
<output>20</output>

<gadget id="calculator">400 - 20</gadget>
<output>380</output>

<result>380</result>