How many numbers can be formed by using three cards with 1, 2, and 3 written on them?
用写有1、2、3的三张卡片，一共可以组成多少个数．
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<gadget id="calculator">3 + 6 + 6</gadget>
<output>15</output>

<result>15</result>