There are 4 classes in the first grade, with 85 boys and 86 girls. There are 5 classes in the second grade, with 102 boys and 105 girls. Ask: How many people per class are there on average for the first and second grades?
一年级有4个班，共有男生85，女生86．二年级有5个班，共有男生102人，女生105人．求：一、二年级平均每班多少人？
<gadget id="calculator">85 + 86 + 102 + 105</gadget>
<output>378</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">378 / 9</gadget>
<output>42</output>

<result>42</result>