Wang Qiang planted 8 trees, Liu Dong planted 9 trees, and Zhang Jie planted 7 trees. How many trees did each of them plant on average?
王强栽了8棵树，刘冬栽了9棵，张杰栽了7棵，他们平均每人栽了多少棵．
<gadget id="calculator">8 + 9 + 7</gadget>
<output>24</output>

<gadget id="calculator">24 / 3</gadget>
<output>8</output>

<result>8</result>