The father is 38 years old this year, and the son is 12 years old this year. How many years later, the age of the father is three times that of the son.
父亲今年38岁，儿子今年12岁，多少年后，父亲的年龄是儿子的3倍．
<gadget id="calculator">38 - 12</gadget>
<output>26</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">26 / 2</gadget>
<output>13</output>

<gadget id="calculator">13 - 12</gadget>
<output>1</output>

<result>1</result>