In the fourth grade, there are 52 students in each class on average, among which there are 55 students in the first class, 48 students in the second class, how many students are there in the third class?
四年级平均每班有52人，其中一班有55人，二班有48人，三班有多少人？
<gadget id="calculator">52 * 3</gadget>
<output>156</output>

<gadget id="calculator">156 - 55 - 48</gadget>
<output>53</output>

<result>53</result>