Variables are a species that reside in the Equation Playground, in the genus Algebraliens. X is the most notable variable, most notable for his role as the co-host of Battle for BFDI and Battle for BFB.
- It was widely believed that variables and integers were the same species, until "The Number Playground Chronicle!" had clarified that the two were in fact separate species.
- Despite having similar characteristics, the GO Guys do not appear to be variables.
|Species: Integers • Variables • Polygons • Irrationals • Operators • Fractions • Polyhedrons
Integers: Zero • One • Two • Three • Four (variations) • Five • Six • Seven • Eight • Nine • Ten