Add 12 to the numerator of (6/14), how much should be added to the denominator to keep the size of the fraction unchanged.
(6/14)的分子加上12，要使分数大小不变，分母要加上多少．
<gadget id="calculator">18 / 6</gadget>
<output>3</output>

<gadget id="calculator">14 * 3</gadget>
<output>42</output>

<gadget id="calculator">42 - 14</gadget>
<output>28</output>

<result>28</result>