Add 5 to the numerator of (5/9), how much should the denominator be multiplied to keep the size of the fraction constant
把(5/9)的分子加上5，要使分数的大小不变，分母应该乘多少
<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">10 / 5</gadget>
<output>2</output>

<result>2</result>