Miquon Math is Magic. It may look totally unimpressive at first, but I promise you that it builds a deep and wide mathematical foundation. And it works equally well for any type of learner. Both those who are naturally mathematically inclined and those who struggle will be given greater mathematical insight when using this program.
The use of Cuisenaire Rods is the KEY to the amazing revelations I have seen children have. It takes a bit of change in mindset for the adult. The goal is exploration, not just memorizing math facts. They WILL memorize those facts, but if you try to make that happen too soon you will cut them off from all the learning that can happen otherwise. Because of that, this program works best for children who are below a 2nd grade level, though some pages could be used as a mini unit for more advanced learners. I put my pages in clear sleeves in a 3-ring binder so they are reusable.
I do math tutoring, so I have a big-picture view of what needs to be learned from K-12th, and it has been incredible to me how often things I learned from using Cuisenaire Rods helped higher level math make sense - multiplying two binomials, factoring polynomials, completing the square, difficult word problems (the Singapore bar model method is essentially an abstract version of Cuisenaire rods), division with remainders, long division, square numbers,.... The concept of saying "of" when reading a multiplication sign was revelational to me when I first saw it as well.
I've also noticed that so much of what is done in Miquon is what is recommended by dyscalculia experts and innovative math experts, but Miquon can be done at a fraction of the cost and research time for the adult.
There are plenty of strong conceptual programs on the market (Singapore, RightStart, Math Mammoth, Mathematics Enhancement Programme, Beast Academy), but if I had to choose just one for lower elementary, this would be it.
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Side note: If the first few pages of the Orange book intimidate you, just skip them! Also, I think the Q section, Simultaneous Equations, is probably too difficult for most kids. It's fine to skip that, too.