Xiao Ming is 12 years old this year, and his father is 36 years old this year. Four years ago, his father's age was how many times that of Xiao Ming's.
小明今年12岁，爸爸今年36岁，4年前，爸爸的岁数是小明的多少倍．
<gadget id="calculator">36 - 4</gadget>
<output>32</output>

<gadget id="calculator">12 - 4</gadget>
<output>8</output>

<gadget id="calculator">32 / 8</gadget>
<output>4</output>

<result>4</result>