<p>I agree with marite, I know that at princeton several of the math majors started in 300 level (Junior) classes, and proceeded to take most of the grad classes required for a PhD from princeton. Depending on the kid it can be very important to have grad classes offered and accessible. This isn;t just true for math, but is true for most of the sciences as well. I took 5 graduate biology classes there, which definitely prepared me better for graduate school and I would have run out of classes to take if I couldn’t have taken the grad classes</p>