Several adults take several children to watch a popular science movie, and the money spent by all adults on buying tickets is exactly 4 times that of all children on buying tickets. It is known that children are half priced, and the total number of people watching movies is 102. Then, How many of them are children?
若干成年人带若干儿童去看科普电影，所有成年人购票所花的钱正好是所有儿童购票所花的钱的4倍，已知儿童半价，看电影的总人数为102人，那么，其中儿童多少人？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">102 / 3</gadget>
<output>34</output>

<result>34</result>