Lanlan is 8 years old this year, and her father is 38 years old this year. When Lanlan is old, her father's age is exactly 4 times that of Lanlan.
蓝蓝今年8岁，爸爸今年38岁，蓝蓝多少岁时，爸爸的年龄正好是蓝蓝的4倍．
<gadget id="calculator">38 - 8</gadget>
<output>30</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">30 / 3</gadget>
<output>10</output>

<result>10</result>