"Why change math? Math is math!"

Not anymore but it used to be 40 years ago or so. Not that it needs to be mandatory there are very few occupations that require Algebra skills. Today a person could learn it in a week using youtube anyway. However, this is all a debate for why the world works the way does specifically all the problems with our education system for another time.

As Tom Lehrer said, the purpose of new math was to understand what you were doing, rather than to get the right answer.

It's issues were that in the name of simplicity it made doing math far more difficult. I was a kid during the height of this. My mother came in one night while I was doing my long division homework. She watched me for a moment and asked why I was filling half the sheet of paper. I showed her the book. She snorted and taught me division as it had been practiced for decades. It was shorter and faster.

Luckily, I was in a Catholic school, that while was using a new math text, was more concerned that I (and my peers) finished the class being able to do math. I never used the new math principles again of standard math. I'd sit through class and then ask my mom or dad to show me the old way. Worked much better.

Different bases were something not taught earlier, and that was useful. And for our typical Americans are stupid foreign friends, my school started us on Algebra in 8th grade. We were into pre-calculus by the time I was a Senior in High School.