Divide the numerator of (2/8) by 2, how much should the denominator be subtracted to keep the size of the fraction constant?
(2/8)的分子除以2，要使分数的大小不变，分母应该减去多少
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

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

<result>4</result>