A couple of weeks ago, my Uber driver was a math teacher in the San Francisco school district. He advised me that if I could afford it, that I should unequivocally send my kids to private school and not to public school. The reason is that they now mix students of all abilities together, instead of separating them out and concentrating on each group separately like they did when we were kids. The thought was the good students would "pull up" and "positively influence" the students with less aptitude. However, what it did instead was to give the incentive to teachers to focus on worse students, who tended to be more disruptive, and essentially abandon the good students and let them fend for themselves. He mentioned that the "independent learners" were identified, and instead of being accelerated, they were left alone so that the poorer students could be concentrated on by the teachers.

As a side note, I don't remember being taught algebra before the 9th grade either, in an excellent school district, and I was in a gifted class. I still kept my algebra textbook from the 10th grade and it's pretty standard algebra. In fact, I didn't even learn Calculus until college and I wasn't negatively impacted by that at all. However, this was almost 30 years ago so I'm sure educational standards have increased, but it's funny that what I learned back then is no longer "good enough".