There are 18 students in Mr. Alvarez's art class. Throughout the year, every student must pair up with every other student to complete a project. How many projects will be finished?

If there are 18 students every one of the will pair up with 17 other students throughout the year so the total amount of pairs that can be made is 18x17=306 but since it's not important if student A is paired with student B or student B with student A we should divide the total amount of pairs by two - 306:2=153 so in total there will be 153 projects finished