Choosing Students for Presentation

In a classroom, there are 5 students: Alex, Ben, Charlie, Diana, and Eva. If the teacher wants to choose 2 students to present their project, how many different ways can the teacher choose the students?

Use the combination formula: $$C(n, r) = \f\frac{n!}{r!(n-r)!}$$ where $n$ is the total number of students and $r$ is the number of students chosen.