There was a country in ancient times, 9 sheep could be exchanged for 3 pigs, and 8 pigs could be exchanged for 2 cows, so how many sheep could be exchanged for one year.
古代有一个国家，9只羊可换3头猪，8头猪可换2头牛，那么一头年可换多少只羊．
<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<result>12</result>