Arbor Day is here, and the school organizes students to plant trees. There are 3 classes in the fourth grade, and a total of 87 trees were planted. How many trees are planted per class on average?
植树节到了，学校组织同学们去植树．四年级有3个班，一共植了87棵树．平均每班植了多少棵树？
<gadget id="calculator">87 / 3</gadget>
<output>29</output>

<result>29</result>