The Texas Essential Knowledge and Skills (TEKS) Standard - TEKS 6.2(A) introduces sixth grade students, for the first time, to the classification of rational, integer, and whole numbers using a Venn Diagram to describe the relationships between the sets of numbers. The standard do not require any mathematical calculations, but it does require an in-depth knowledge and understanding of the theory of the Universal Set, Sets, and Subsets including the definitions associated with sets and their ind