There are 4 classes in the fourth grade, each class is divided into 2 groups on average, and 104 trees are going to be planted, how many trees are planted in each group on average?
四年级有4个班，每班平均分成2个组，准备植树104棵，平均每组植树多少棵？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">104 / 8</gadget>
<output>13</output>

<result>13</result>