Add 4 to the numerator of (8/36), how much should be added to the denominator to keep the fraction size unchanged
(8/36)的分子加上4，要使分数大小不变，分母应加上多少
<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">12 / 8</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">36 * (3/2)</gadget>
<output>54</output>

<gadget id="calculator">54 - 36</gadget>
<output>18</output>

<result>18</result>