Xiaohua is 11 years old and Honghong is 13 years old. What is their average age?
小花11岁，红红13岁，两人的平均年龄是多少岁．
<gadget id="calculator">11 + 13</gadget>
<output>24</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<result>12</result>