[jakderrida]

> stressful for kids and disengage from the subject

In my limited experience, stress and disengagement are almost always the main culprit. Once someone decides, "I'm not good at math", it becomes a lost battle that they'll pretty much never revisit or seek to relitigate.

In my family growing up, we were all taught Algebra as early as 4th grade by our mom because the Philadelphia Catholic School system taught some absurd system where everything a simple education in Algebra can solve is replaced with a massive blackboard-covering table of rules to memorize that I wish I had a picture of because nobody believes me. Anyway, knowing Algebra helped all of my siblings get far enough ahead of the class that most everyone else disengaged while we excelled and younger siblings were frequently helped to advance even better because they had a house packed with people that liked math.