An owl eats 20 voles every day. According to this calculation, in February 2008, how many voles the owl ate.
一只猫头鹰每天吃20只田鼠，照这样计算，2008年的二月，这只猫头鹰吃多少只田鼠．
<gadget id="calculator">20 * 29</gadget>
<output>580</output>

<result>580</result>