Complex sentence: It is a part of elementary school, a school providing instruction for young pupils, comprising traditionally of grades k-6,in Some school districts, Fourth Grade is the First year of intermediate school or the last year of elementary.
Split into simpler sentences: It is a part of elementary school, a school providing instruction for young pupils, comprising the first three, four, or five grades of a student's educational career. In Some school districts, Fourth Grade is the First year of intermediate school or the last year of elementary.