20 rabbits can be exchanged for 2 sheep, 9 sheep can be exchanged for 3 pigs, 6 pigs can be exchanged for 2 cows, and 12 cows can be exchanged for how many sheep.
20只兔可换2只羊，9只羊可换3只猪，6头猪可换2头牛，12头牛可换多少只羊．
<gadget id="calculator">9 * 10</gadget>
<output>90</output>

<gadget id="calculator">90 * 12</gadget>
<output>1_080</output>

<gadget id="calculator">1_080 / 10</gadget>
<output>108</output>

<result>108</result>