Class 31 was divided into 5 groups to participate in tree planting. A total of 280 trees were planted, with an average of 7 people in each group. How many trees were planted by each person on average?
三1班分成5个小组，参加植树，共植树280棵，平均每组7人，平均每人植树多少棵？
<gadget id="calculator">7 * 5</gadget>
<output>35</output>

<gadget id="calculator">280 / 35</gadget>
<output>8</output>

<result>8</result>