 Universal algebra is the next level of abstraction after abstract algebra. Whereas elementary algebra treats equational reasoning in a particular algebra such as the field of reals or the field of complex numbers, and abstract algebra studies particular classes of algebras such as groups, rings, or fields, universal algebra studies classes of classes of algebras. Much as abstract algebra numbers groups, rings, and fields among its basic classes, so does universal algebra count varieties, quasivarieties, and elementary classes among its basic classes of classes.