If you subtract 9 from the numerator of (12/16), what should the denominator be divided by to keep the size of the fraction constant?
如果把(12/16)的分子减去9，要使分数的大小不变，分母应除以多少
<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<result>4</result>