In the reading contest, Xiao Zhu read 6 books, Xiao Ming read 4 books, Xiao Hua read 3 books, Xiao Jun read 7 books, how many extra-curricular books each person read on average.
在读书比赛中，小朱读了6本，小明读了4本，小华读了3本，小军读了7本，平均每人读多少本课外书．
<gadget id="calculator">6 + 4 + 3 + 7</gadget>
<output>20</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<result>5</result>