There are 132 students in the fourth grade who took the Chinese and mathematics exams, and each of them got excellent results in at least one subject. Among them, there are 75 people with excellent Chinese performance and 78 people with excellent mathematics performance. How many people are excellent in Chinese and mathematics?
四年级有132名学生参加语文、数学考试，每人至少有一门功课取得优秀．其中语文成绩优秀的有75人，数学成绩优秀的有78人．语文、数学成绩都优秀的有多少人？
<gadget id="calculator">78 - 132</gadget>
<output>-54</output>

<gadget id="calculator">75 + (-54)</gadget>
<output>21</output>

<result>21</result>