The denominator of (2/3) is increased by 12, how much should the numerator be increased to keep the size of the fraction constant
(2/3)的分母增加12，要使分数的大小不变，分子应增加多少
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>