Add 6 to the numerator of (3/10), what should be the denominator to keep the fraction constant.
(3/10)的分子加上6，要使分数大小不变，分母应多少．
<gadget id="calculator">3 + 6</gadget>
<output>9</output>

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

<result>3</result>