I hope that 5 classes of Grade 4 will participate in the tree planting activity. On the first day, 28 trees will be planted, on the second day, 20 trees will be planted, and on the third day, 32 trees will be planted. The following calculation formula is to calculate the average number of trees planted per class.
希望小学四年级5个班参加植树活动，第一天植树28棵，第2天植树20棵，第3天植树32棵，下面多少算式是求平均每班植树多少棵．
<gadget id="calculator">28 + 20 + 32</gadget>
<output>80</output>

<gadget id="calculator">80 / 5</gadget>
<output>16</output>

<result>16</result>