In class 31, 32 people subscribed to "Mathematics Journal", 30 people subscribed to "Reading Newspaper", 10 people subscribed to both newspapers, and everyone in the class subscribed to at least one kind of newspaper. How many students are there in Class 3 and Class 1?
三1班订《数学报》的有32人，订《阅读报》的有30人，两份报纸都订的有10人，全班每人至少订一种报纸．三1班共有学生多少人．
<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<gadget id="calculator">32 + 20</gadget>
<output>52</output>

<result>52</result>