Xiaoming is 8 years old this year, Xiaoqiang is 7 years old, Xiaohong is 5 years old, Xiaogang and Xiaoming are the same age, what is the average age of the four of them this year?
小明今年8岁，小强7岁，小红5岁，小刚和小明同岁，今年他们四人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>