[blindkid] Elementary math question

[b&s]

Emilia is now in 4th grade. I have been going in occasionally to help/observe during gen ed math time. I have always understood that the teaching of math (and all subjects for that matter) is vision centric. This is just a fact of life and I've been under the impression that teaching a blind kid is just a matter of tweaking the same information that is taught to the sighted kids. However, What struck me yesterday was the possibility that entire portions of the math curriculum may be fundamentally dependent on a visual approach, so that the issue becomes one, not of transcribing, but of truly translating the concepts to an entirely different language….and possibly even throwing out portions of the curriculum. This came up while thinking about number lines. Number lines figure heavily in the teaching and testing at this level. Emilia has a brailled number line at school that does a reasonable job of transcribing the visual information. She can read the number line and mimic what other kids are doing with some effort. My question is whether a brailled number line is really useful to a congenitally blind student to help with understanding the underlying concepts?….or does it just make us sighted folk feel good about seeing the blind kid do the same thing the sighted kids are doing? Is she really learning the material?

Unless I'm missing something, the abacus seems to cover the same territory and more as the number line. I don't even know how to approach the notion of the hundreds chart, which again, is available in braille, but is it really useful? If the answer is no, then there is the question of how to approach the issue of class participation, when everyone else is using these tools and concepts. 

I plan to talk to a couple of congenitally blind adult friends to get their perspective on this stuff. Any enlightenment from parents and others here would be great also. 

Thanks, Brandon