Nowadays many middle schools post their "program of studies" online. At our middle school grade 6 math is undifferentiated. The grade 7 and 8 math courses, in decreasing order of difficulty, are

7:
Advanced Algebra 7
Algebra 7
Pre-algebra

8:
Advanced Algebra II
Algebra II
Algebra 8
Pre-Algebra 8

At the open house for 6th grade parents, the principal emphasized that the tracks in math and other subjects had some flexibility. Each math course can lead to two or more future math courses, depending on performance. So Algebra 7 students can in theory go into Advanced Algebra II the following year.