The numerator of (5/9) is increased to 15, how much should the denominator be increased to keep the fraction value unchanged
(5/9)的分子增加到15，要使分数值不变，分母要增加多少
<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<gadget id="calculator">27 - 9</gadget>
<output>18</output>

<result>18</result>