Ask them for their research.
I am not an expert on this, but I recall studies saying that learning to play an instrument at a young age can help kids do better in math (something about growing brain connections?).
I also think there are studies showing a correlation between musical talent and math talent. Of course, correlation is only correlation. And that doesn't mean that if a kid is good in one they are automatically good in another.
Why not just test kids to see if they are good in math?
None of this means the research doesn't exist. . .I think it would be interesting to read it.
