Xiaowei's family has 20 rabbits, and the number of big rabbits is 4 times that of the small rabbits, so how many big rabbits are there in Xiaowei's family?
小卫家里养了20只兔子，其中大兔只数是小兔的4倍，那么小卫家养的大兔有多少只．
<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">20 / 5</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>