There are 3 classes in the third grade with an average of 40 students in each class. There are 41 people in the first class, 37 people in the second class, and how many people are in the third class.
三年级3个班平均每班有学生40人．其中一班有41人，二班有37人，三班有多少人．
<gadget id="calculator">40 * 3</gadget>
<output>120</output>

<gadget id="calculator">120 - 41 - 37</gadget>
<output>42</output>

<result>42</result>