These are 20 (easy-hard) chemical equations that need to be balanced. One side of the card has a letter "H,A,P,P,Y..." to spell Happy Halloween! The other side of the card has the equation. It is played as a game that is won when all equations are balanced and it spells "Happy Halloween" across the students' groups' desks. There are 2 that are already balanced thrown in there also. Great for physical science class or chemistry class.