Newmath.club
Courses in
Mathematics for
Junior High School Teachers,
High School
Elementary School to College
Levels 0 for kindergarten to
Level 15 college.

The levels are loosely associated with Grades, so Level 7, is Grade 7, Junior High School.

There are dozens of texts at each level, with problems, answers, and samples. The courses are interconnected, meaning, Level 7 assumes proficiency and knowledge for levels 1 to 6. If unable to handle level 7, back down to level 6 or 5, or to whatever level proficiency is obtained. Then proceed with the work.

The material is from the School Mathematics Study Group circa 1950s to 1970s, financed by the National Science Foundation.