If 20 rabbits can be exchanged for 2 sheep, 9 sheep can be exchanged for 3 pigs, and 8 pigs can be exchanged for 2 cows, then how many rabbits can be exchanged for 100 cows.
假如20只兔子可以换2只羊，9只羊可以换3头猪，8头猪可以换2头牛，那么用100头牛可以换多少只兔子．
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">12 * 10</gadget>
<output>120</output>

<gadget id="calculator">120 * 100</gadget>
<output>12_000</output>

<result>12_000</result>