There are four number cards 1, 2, 3, and 4. Take 3 cards each time to form a three-digit number. How many odd numbers can be formed.
有1、2、3、4四张数字卡片，每次取3张组成一个三位数，可以组成多少个奇数．
<gadget id="calculator">2 * 3 * 2</gadget>
<output>12</output>

<result>12</result>