There are 30 students in Class 1 of the second grade. In the final exam, there are 24 students who got "Excellent" in Chinese, and 25 students who got "Excellent" in Mathematics, and each of them got "Excellent" in at least one subject. You know that they both got "Excellent" How many "excellent" students are there?
二年级一班有30名学生，期末考试中语文得"优"的有24名，数学得"优"的有25名，而且每人都至少有一门得"优"，你知道两门都得"优"的学生有多少名吗？
<gadget id="calculator">25 - 30</gadget>
<output>-5</output>

<gadget id="calculator">24 + (-5)</gadget>
<output>19</output>

<result>19</result>