The focus is on experience, understanding and perspective --- and fits *perfectly* with Montessori elementary mathematics, geometry and algebra.
Indeed, if you have used Montessori elementary and now have an adolescent - continuing with the suggestions here and doing a study of history, would be perfect for the adolescent child. Even into high school!
The site owner also has a set of lesson plans for math history and skills called Living Math Through History
-- and she has a Yahoo group for folks to join for support and questions: LivingMathForum
You do NOT need to be using her lesson plans to be part of the group.

http://livingmath.net/