Xiaojun is 9 years old this year, his father is 4 times his age, how old is his father?
小军今年9岁，爸爸的年龄是小军的4倍，爸爸比小军大多少岁？
<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">36 - 9</gadget>
<output>27</output>

<result>27</result>