Add 14 to the numerator of (7/12), how much should be added to the denominator to keep the fraction size constant
(7/12)的分子加上14，要使分数大小不变，分母应该加上多少
<gadget id="calculator">7 + 14</gadget>
<output>21</output>

<gadget id="calculator">21 / 7</gadget>
<output>3</output>

<gadget id="calculator">12 * 3</gadget>
<output>36</output>

<gadget id="calculator">36 - 12</gadget>
<output>24</output>

<result>24</result>