Originally Posted by Val
I looked through the grades 5-8 books and discovered that they don't really present a ton of novel material. They mostly seem to do the same stuff with bigger numbers.

You are absolutely right about this. When I was in grad school I worked as a long-term substitute for about a semester teaching 7th & 8th grade math. Each day I taught the same thing in my 7th grade classes as I did in my 8th grade classes with usually only an order magnitude difference in the numbers. I definitely don't recommend 6th-8th grade math for gifted students.

There was a good discussion on this topic in the "EG/PG and not accelerated?" thread.