Answer:
The number of remaining students in the library is 14.
Explanation:
The total number of students in the library is 27.
If students arrive in the library, then the number of students in the library will increase. If student left the library, then the number of students in the library will decrease.
It is given that 7 children left the library it means the number of student in the library will reduced by 7.
The remaining students are
![21-7=14](https://img.qammunity.org/2020/formulas/mathematics/middle-school/3himyq5vl9mg3nrtgmmxnipeyilukf2ovb.png)
Therefore, the number of remaining students in the library is 14.