The age difference between mother and son is 28 years, and the age ratio of mother and son is 3:1, so how old is the son?
母子俩的年龄差是28岁，母子的年龄比是3：1，那么儿子是多少岁岁．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">28 / 2</gadget>
<output>14</output>

<result>14</result>