If the numerator of a fraction is increased by 3 times, how many times should the denominator be enlarged to keep the size of the fraction constant?
一个分数的分子增加3倍，要使分数的大小不变，分母应该扩大多少倍
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>