There are 4 classes in the fourth grade, with a total of 182 students. Among them, there are 84 people in Class 1 and Class 2, 91 people in Class 2 and Class 4, and 87 people in Class 1 and Class 4. How many people are there in Class 3?
四年级有4个班，共182人．其中一班与二班共84人，二班与四班共91人，一班与四班共87人，那么三班有多少人？
<gadget id="calculator">84 + 91 + 87</gadget>
<output>262</output>

<gadget id="calculator">262 / 2</gadget>
<output>131</output>

<gadget id="calculator">182 - 131</gadget>
<output>51</output>

<result>51</result>