An uncle asked "Little Clever" how old he was, and he said, "Twice my age three years from now minus twice my age three years ago, is equal to my current age." Clever "How old is this year?
有位叔叔问"小机灵"几岁了，他说："我三年后年龄的2倍减去我三年前年龄的2倍，就等于我现在的年龄．"小朋友想一想，"小机灵"今年几岁了？
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">6 + 6</gadget>
<output>12</output>

<result>12</result>