Subtract 12 from the numerator of (18/24), how much should be subtracted from the denominator to keep the size of the fraction unchanged.
把(18/24)的分子减去12，要使分数的大小不变，分母应减去多少．
<gadget id="calculator">18 - 12</gadget>
<output>6</output>

<gadget id="calculator">18 / 6</gadget>
<output>3</output>

<gadget id="calculator">24 / 3</gadget>
<output>8</output>

<gadget id="calculator">24 - 8</gadget>
<output>16</output>

<result>16</result>