There are 48 students in class 31, 30 students participated in the art group, 24 students participated in the music group, how many people participated in both interest groups.
三1班有48名同学，30名同学参加了美术小组，24名同学参加了音乐小组，两个兴趣小组都参加的有多少人．
<gadget id="calculator">24 - 48</gadget>
<output>-24</output>

<gadget id="calculator">30 + (-24)</gadget>
<output>6</output>

<result>6</result>