In the second class of the third grade, 28 people subscribed to "Intellectual Games", 22 people subscribed to "Science Fiction World", 10 people subscribed to both newspapers and periodicals, and 7 people subscribed to neither newspaper and periodical. How many people are there in Class 2, Grade 3?
三年级二班有28人订了《智力游戏》，有22人订了《科幻世界》，两种报刊都订的有10人，两种报刊都没订的有7人．三年级二班一共有多少人？
<gadget id="calculator">22 - 10</gadget>
<output>12</output>

<gadget id="calculator">28 + 12 + 7</gadget>
<output>47</output>

<result>47</result>