Thanks, Orphan. That's what I remember from 20 years ago, so, yeah, I could be mixing things up a bit.
I just remember being explicitly instructed to purchase yellow, cyan blue, and fuchsia paints for all of our painting. Whether they were called primary or not escapes me.
Now that I think about it, there was some discussion about the primary colors of light being different than the primary colors of pigment, but, again, that was 20 years ago.