Meizi is 9 years old, Xiaolan is 6 years old, Xiaoming is 4 years old, Xiaowu and Meizi are the same age, what is their average age?
梅子9岁，小兰6岁，小明4岁，小午和梅子同岁，他们的平均年龄是多少岁．
<gadget id="calculator">9 + 6 + 4 + 9</gadget>
<output>28</output>

<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<result>7</result>