There are seven liberal arts: grammar, dialectic (logic), rhetoric, aesthetics (music), empirics (astronomy), mathematics, and geometry. The first three make up what is known as the trivium, literally the three-fold way. The remaining four make up the quadrivium. This is a natural division to make between them because the first three all emphasize the study of language and thinking. The remaining four concern some form of or are centered on mathematics.
This was the course of study for any “educated” man (or even woman) from age 7 to age 21. Upon completion, the student was ready for a more specialized graduate study. All of the liberal arts have a place in a K through 12 education today, but the trivium is central for a school that teaches classically. Grammar, logic, and rhetoric are not simply subjects as we use that term today to describe history, literature, or science. They describe a systematic approach to learning with the goals of wisdom and eloquence.