There are 6 cowsheds in a dairy farm, and there are 7 cows in each cowshed. A total of 840 kg of feed is fed a day. How many kg of feed is fed to each cow on average?
奶牛场有6个牛棚，每个牛棚中有7头奶牛．一天共喂840千克饲料，平均每头奶牛一天喂多少千克饲料？
<gadget id="calculator">6 * 7</gadget>
<output>42</output>

<gadget id="calculator">840 / 42</gadget>
<output>20</output>

<result>20</result>