Xiaohua is 13 years old this year, and his father is 9 years younger than four times his age. How old is his father this year?
小华今年13岁，爸爸的年龄比他的4倍少9岁，爸爸今年多少岁？
<gadget id="calculator">13 * 4</gadget>
<output>52</output>

<gadget id="calculator">52 - 9</gadget>
<output>43</output>

<result>43</result>