Noble Saxon Math. They’ve tried to rope it into the mediocracy, and they’re trying to do the same thing with noble Singapore Math.
Best to use the older versions of the books. Just looked at a couple of ours and they’re Second Edition from the 80s-90s. Back in the day, I made a list of all the ISBN numbers that would make a complete set. Then you need answer booklets to match.
The last person who understood all of mathematics died 75 years ago. It is a window that was once a stained-glass whole but has now started cracking. Dark masters like Francis Dalton’s rendering of what was once straightforward fact, into the religion of science as omniscience, contributed to the decay. If “science” were in charge of the Gordian Knot of Covid19 controversies, there would be a multi-national insistence on a top, U.N. commission to straighten out the mess, on the basis of rigorous peer reviews, a kind of lethal gymnasium of the mind. Instead, the world of “science” is running around like a roach-infested kitchen when someone has started knocking on the walls. We are entering a new dark ages. It’s up to the regular people living out on the margins to keep together the remnants of what was once a great civilization.