Add 4 to the numerator of (1/5), how many times should the denominator be enlarged to keep the size of this fraction constant
(1/5)的分子加上4，要使这个分数的大小不变，分母应该扩大多少倍
<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<result>5</result>