Add 6 to the numerator of (2/9), how much should be added to the denominator, and the size of the fraction remains unchanged.
(2/9)的分子加上6，分母应该加上多少，分数的大小不变．
<gadget id="calculator">2 + 6</gadget>
<output>8</output>

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

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">36 - 9</gadget>
<output>27</output>

<result>27</result>