The sum of the ages of the father and son is 70 years, and the age of the father is 6 years less than three times the age of the son. How old is your son this year?
父亲与儿子的年龄和是70岁，父亲的年龄比儿子的年龄的3倍少6岁．今年儿子多少岁．
<gadget id="calculator">70 + 6</gadget>
<output>76</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">76 / 4</gadget>
<output>19</output>

<result>19</result>