Add 6 to the numerator of (3/4), how much should be added to the denominator to keep the size of the fraction constant?
(3/4)的分子加上6，要使分数的大小不变，分母应该加上多少？
<gadget id="calculator">3 + 6</gadget>
<output>9</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

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

<gadget id="calculator">12 - 4</gadget>
<output>8</output>

<result>8</result>