Class Four 1 has 55 people, Class Four 2 has 52 people, Class Four 3 has 49 people. How many people do they have on average per class? (Please list the comprehensive formula answer)
四1班有55人，四2班有52人，四3班有49人．他们平均每班有多少人？(请列综合算式解答)
<gadget id="calculator">55 + 52 + 49</gadget>
<output>156</output>

<gadget id="calculator">156 / 3</gadget>
<output>52</output>

<result>52</result>