A group of students are talking. 2 friends leave the group. Write an expression for the number of students in the group after 2 leave.
1) Well since you don't know how many students there were in the whole group then you use a variable, which in this case we could use an "S" to stand for students.
2) Then you have to subtract 2, because 2 people left the group which is called an expression.
So the answer would be S-2.