So I've been reading some of the old New Math textbooks from when this was a thing in the US. Pic related is for 8th graders; and is the introduction to the bit on measuring areas of rectangles.

What does /sci/ think? Was teaching stuff like group theory to kids a great way to get them to really understand and appreciate maths? Or was teaching them an abstract set-theoretical basis for basic intuitive concepts a load of pointless wankery?