Oh, I SOOOOOO agree, Lorel! I love, love, LOVE this way of thinking! I suspect it's what the spiral curriculum aspires to be, but doesn't usually quite reach. It's why we're doing calculus and physics this year, with our highly conceptual but not very arithmetic-y 7yo.

Give 'em a real challenge, let 'em get what they can, then give it to 'em again a little harder in 2 or 3 years. I think it's brilliant!

Kriston