A certain school has 96 students in the first grade, 140 students in the second and third grades, and 168 students in the fourth grade. How many students are there on average in each grade?
某校一年级有学生96人，二年级和三年级平均有学生140人，四年级有168人，平均每个年级有多少人？
<gadget id="calculator">96 + 140 + 140 + 168</gadget>
<output>544</output>

<gadget id="calculator">544 / 4</gadget>
<output>136</output>

<result>136</result>