A pig can be exchanged for 2 sheep, a sheep can be exchanged for 3 chickens, and a pig can be exchanged for how many chickens.
一头猪可以换2只羊，一只羊可以换3鸡，一头猪可以换多少只鸡．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<result>6</result>