K-6 is an abbreviation for the grades in school from kindergarten through sixth grade. K-6 stands for primary, or elementary school. It would refer to the first seven years of a child’s formal education.

Ways of educating children vary from country to country and even within those countries. Usually, primary school is compulsory, and ranges anywhere from kindergarten to eighth grade. Sometimes kindergarten is considered pre-school, and often there is a middle school or a junior high school between the primary and secondary schools. There are many variations of this, with school districts sometimes making decisions based on the population of school age children and facilities available. For example, this could mean a middle school, if it is large, may hold an extra grade.
The term “primary school” is more widely used in the world than the term “elementary school” which is mainly used in North America. Primary schools are sometimes called grammar schools. Elementary schools used to teach the three “Rs”: Reading, Writing, and Arithmetic, but we have come a long way since then.
The term “primary school” comes from the French “ecole primaire.” An overview of the curriculum in primary school will help clarify the meaning of K-6. Core subjects in all schools are reading or language arts, math, science, and social studies.
Additional classes include art, music, computers and keyboarding, and physical education (PE).
Primary school is not just about curriculum. The child will also learn necessary skills for living in society. He will learn tolerance, how to make and keep friends, and how to respond to certain situations. He will also discover things about himself, things he is good at, and things that he likes and dislikes. Hopefully, he will also learn perseverance, and develop a good work ethic.
Looking at secondary schools will further answer your questions about K-6 because that is the next step for most primary school graduates.
Secondary schools are considered to be the final stage of education, with all or part of it being compulsory. It usually lasts no longer than six years. It continues the core classes of language arts, math, science, and social studies, but offers more specialization such as:
Many offerings are dependent on college entrance requirements, with some schools having a college preparation track for students who will continue on to college.
Elementary education has a specialized field called early childhood education. It covers the ages from birth to eight. These are a child’s formative years, and good education is essential to the child’s future development, both physically and mentally. Most colleges offer classes and degrees, or at least majors, in early childhood education. Most states have a special endorsement on teacher’s licenses for early childhood.
Early childhood curriculum explores the child’s cognitive, emotional, and physical development from birth to eight years old. There are also classes on special needs children, with both physical and mental challenges, and classes dealing with childhood diseases and other things that can interfere with proper development. Basically, early childhood education studies the whole child, and what is needed to ensure that the child grows and develops through all the stages of early life.