Aggregation functions are important tools that help teachers understand how well students are doing over time. Some common functions you might hear about include COUNT, AVG, SUM, and MAX. When teachers use these functions along with the GROUP BY clause, they can do some pretty neat things:

1. Find Average Grades: Teachers can find out the average grade for a class by using $AVG(grade)$. This helps them see how the class is doing overall.

2. Count Student Enrollment: They can also count how many students are enrolled each semester by using $COUNT(student_id)$. This helps teachers keep track of how many students are signing up.

3. Look at Performance by Groups: By grouping students based on their backgrounds, teachers can compare how different groups are performing. This helps to identify any differences in grades.

These tools help teachers make smarter decisions and come up with ways to support students who might need extra help!