3 cats eat 3 mice in 3 days, at this rate, how many mice will 9 cats eat in 9 days?
3只猫3天吃3只老鼠，照这样的速度，9只猫9天吃多少只老鼠．
<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<result>27</result>