This text highlighted some key examples of how different textbooks represent mathematical ideas differently. The ones that stood out to me were how absolute values, the binomial coefficient, and derivatives were all somehow represented with different lenses. It is expected that the arts will have different biases, but it is not expected for bias to emerge in STEM subjects such as math. Because bias is not expected, its presence is even more insidious.
I have talked about textbooks at great lengths with my SAs. In order to teach the current grade 10 curriculum, I require 3 different textbooks. This is because the curriculum keeps changing and the textbooks quickly become out of date. Because textbooks are static by nature they are not good teaching tools for the changing environment of learning.
My final thoughts on textbooks is that they teach material a certain way, and it might not line up with the way I view that topic of math. I will be biased in my own teaching, but I think that as an educator, it is better to teach well with your own bias than to teach a choppy, inauthentic lesson with someone else's bias. Students learn best from teachers who are passionate about the material, and that passion might disappear if I was forced to teach math in an inauthentic way.