When I was a kid, math was always difficult for me. I didn't have a natural ability and neither of my parents knew much more about math beyond multiplication and division. I was pretty much on my own to learn geometry, trigonometry and algebra.
This was part of the reason I worked so hard learn math because I didn't want my children to have to learn the same way I did. The good news is that I can take my children all the way through advanced calculus, I am sure it will all come back to me, but I don't want to pressure or push them.
It's too easy to push children these days and make it so they don't want to learn it. My son has a natural knack for math and I want to feed that. He's is genuinely interested in numbers and I will do whatever I can to nurture this gift. I have no problem teaching him concepts that are beyond his grade level if he wants to learn it, but I will stop short of becoming a domineering father. If my son wants to be a scientist or mathematician, then great. If not, then that's OK too.