I'm now remembering even more of the New Math that was remaining in my elementary school education (1966-72): I always remember set theory in 3rd grade (not par

I'm now remembering even more of the New Math that was remaining in my elementary school education (1966-72): I always remember set theory in 3rd grade (not particularly motivated as I remember, but very neat, a useful way to help describe the world), 4th grade as I recall is where non-decimal bases were introduced. And of course it had that obvious effect (at least for me). This was in Joplin, MO, one of the reddest Red State parts of the country, albeit in a school district famous after the 1955 publication of Why Johnny Can't Read for still being able to teach its students how to read. But the language arts were always very capably taught in the district, generally better than math.