We just started using Numicon math with our son J. (11) who has Down Syndrome this last fall. He has never gotten into any type of math. We have counted anything and everything, used Math U See, and I have studied the book Teaching Math to People With Down Syndrome, plus who knows what else. Nothing has worked.
He loves it
I would recommend it to anyone beginning to learn numbers, not just those with special needs. J can now add numbers up to 10, he can count his answer and tell you how many. We are still working on what each number looks like as he still mixes them up, but he is understanding it.