Bear (5) can read, but we have no idea how well. He can do math, same issue. He won't demonstrate even for us, in fact he flat out tells us "I can't read!" when confronted with the fact that we saw him doing so. I wonder if it's a learned behavior ("Three year olds can't read") or just his anxiety of not doing it right the first time...

Wish I had more to offer you, but at least you aren't alone!