16 rabbits can be exchanged for 2 sheep, 15 sheep can be exchanged for 5 pigs, and 9 pigs can be exchanged for how many rabbits.
16只兔可换2只羊，15只羊可换5头猪，9头猪可换多少只兔．
<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<gadget id="calculator">3 * 9</gadget>
<output>27</output>

<gadget id="calculator">8 * 27</gadget>
<output>216</output>

<result>216</result>