The 6 fourth-grade classes at Marathon Elementary School are having a kick-ball tournament. Each class must play each other one in the tournament. How many kick-ball games must be scheduled?

2 answers

6x6=36 games
There will be (6x5)/2 or 15 games

(class A cannot play against classA, as would be the case in lisa's answer.
I also divided by 2 since class B vs class C is the same game as class C vs class B etc)