There are 48 students in class 31, 30 students participated in the Chinese interest group, 26 students participated in the mathematics interest group, how many people participated in both interest groups.
三1班有48名同学，30名同学参加了语文兴趣小组，26名同学参加了数学兴趣小组，两个兴趣小组都参加了的有多少人．
<gadget id="calculator">26 - 48</gadget>
<output>-22</output>

<gadget id="calculator">30 + (-22)</gadget>
<output>8</output>

<result>8</result>