Wei Mengru is 8 years old this year. In 4 years, his father will be three times the age of Wei Mengru. How old is his father this year?
韦梦茹今年8岁，再过4年，爸爸的年龄是韦梦茹的3倍，爸爸今年多少岁？
<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">12 * 3</gadget>
<output>36</output>

<gadget id="calculator">36 - 4</gadget>
<output>32</output>

<result>32</result>