Add 16 to the numerator of (4/7), if the size of the fraction remains the same, how much should be added to the denominator
(4/7)的分子加上16，如果分数的大小不变，分母应加上多少
<gadget id="calculator">4 + 16</gadget>
<output>20</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">7 * 5</gadget>
<output>35</output>

<gadget id="calculator">35 - 7</gadget>
<output>28</output>

<result>28</result>