Xiaohong is 8 years old, Xiaodong is 5 years old, Xiaoming is 7 years old, Xiaogang and Xiaohong are the same age, what is their average age?
小红8岁，小东5岁，小明7岁，小刚和小红同岁，则他们的平均年龄是多少岁．
<gadget id="calculator">8 + 7 + 5 + 8</gadget>
<output>28</output>

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

<result>7</result>