When choosing a math course, many parents decide to go with one publishing company and stick with them throughout their student’s education because math courses are assumed to “build on each other”. And yes, math does build on itself, that’s why we have a typical course sequence, but be aware that some companies play the game of writing courses in such a way that you actually need to take their next course to fill in the gaps, but it shouldn’t be this way.
Math is a very real science and the truths you learn in math are the same for everyone. So no matter what publishing company puts them on paper, you should still be learning math.
There is nothing more significant about a good geometry course from company A and a good geometry course from company B as long as both companies A and B cover geometry well. There might be some differences as far as how each company covers the material; one company might provide more example problems than another. One company may have more real life examples than the second company. Or perhaps you like the number of available homework problems in one book over another. Those differences might make your choose Company A over Company B, but there should not be a requirement to take courses from the same publishing company in order to get a good education.
