Xiao Ming is 8 years old, Xiao Hong is 9 years old, Xiao Xu is 7 years old, and Xiao Gang is 3 years old. What is their average age?
小明8岁，小红9岁，小旭7岁，小刚3岁，他们的平均年龄是多少岁．
<gadget id="calculator">8 + 9 + 7 + 3</gadget>
<output>27</output>

<gadget id="calculator">27 / 4</gadget>
<output>27/4 = around 6.75</output>

<result>27/4 = around 6.75</result>