Add 15 to the numerator of (5/8), how much should be added to the denominator to keep the fraction constant
(5/8)的分子加上15，要使分数大小不变，分母应加上多少
<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">32 - 8</gadget>
<output>24</output>

<result>24</result>