Add 9 to the numerator of (3/8), how much should be added to the denominator to keep the fraction size unchanged.
(3/8)的分子加上9，要使分数大小不变，那么分母应加上多少．
<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<result>24</result>