Add 9 to the numerator of (3/8), how much should the denominator be multiplied to keep the fraction constant?
(3/8)的分子加上9，要使分数大小不变，分母应乘以多少
<gadget id="calculator">3 + 9</gadget>
<output>12</output>

<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<result>4</result>