There are 48 people in class 3 and 3, among them 37 people like art and 41 people like music. How many people like both art and music? (Everyone likes at least one of them)
三3班有48人，其中喜欢美术的有37人，喜欢音乐的有41人．既喜欢美术又喜欢音乐的有多少人？(每人至少喜欢其中一门)
<gadget id="calculator">41 - 48</gadget>
<output>-7</output>

<gadget id="calculator">37 + (-7)</gadget>
<output>30</output>

<result>30</result>