Dad is 30 years older than Xiao Ming. Three years later, Xiao Ming will be his father's age (1/3). How old is Xiao Ming this year?
爸爸比小明大30岁，三年后小明年龄是爸爸的(1/3)，求小明今年几岁？
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">15 - 3</gadget>
<output>12</output>

<result>12</result>