The article talks about changing "Algebra 1" to the 9th grade, so, as an outsider I have to ask: Is "Algebra 1" the codename for an intermediate or advanced alg

The article talks about changing "Algebra 1" to the 9th grade, so, as an outsider I have to ask: Is "Algebra 1" the codename for an intermediate or advanced algebra class (and before that basic algebra is just taught in a general "Math" class)? Or is "Algebra 1" literally the first time the students are presented with the concepts of algebra? I was curious and followed some of the links in the article, some of the PDFs seem to imply that the first concepts of algebra are in fact introduced in grade 6 (which wouldn't be too bad). But I couldn't find a definitive answer (I got bored by too many policy documents and couldn't find an actual curriculum document).