The chickens in the chicken farm can eat 99 kilograms of food in 3 days. According to this way of eating, how many kilograms of food can these chickens eat in a week?
养鸡场的鸡3天能吃99千克食物．按这种吃法，这些鸡一个星期能吃食物多少千克？
<gadget id="calculator">99 / 3</gadget>
<output>33</output>

<gadget id="calculator">33 * 7</gadget>
<output>231</output>

<result>231</result>