In 3:8, if 9 is added to the former term, how many times should the latter term be enlarged to keep the ratio constant.
在3：8中，如果前项加上9，要使比值不变，后项应该扩大多少倍．
<gadget id="calculator">3 + 9</gadget>
<output>12</output>

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

<result>4</result>