There are a total of 121 students in the three classes of the third grade. The number of students in class 1 and class 3 is equal. There are 39 students in class 2. How many students are there in class 1 and class 3?
三年级三个班共有学生121名学生，一班和三班学生人数相等，二班有39人，一班和三班各有多少人？
<gadget id="calculator">121 - 39</gadget>
<output>82</output>

<gadget id="calculator">82 / 2</gadget>
<output>41</output>

<result>41</result>